Mars Core/Walkthrough

Doom Eternal walkthroughs
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Cultist Base Super Gore Nest ARC Complex Mars Core Taras Nabad
The Ancient Gods, Part Two
The World Spear

This page contains walkthroughs for the standard and Master Level versions of Mars Core, the seventh level of Doom Eternal.

Standard level

Objectives

Shoot a hole in Mars

Get to the BFG-10000

Retrieve the power source

Evacuate the Phobos base

Reach the portal

Use the ion catapult

Get to the escape pod

Essentials

The BFG-10000

Once the elevator reaches its destination, kill the prowler and mecha zombies in front of you then enter the passage they came from to dispose of some imps. Look up when you reach the end of the passage to see a vent opening and climb into it, then punch through the cracked grate on your right to enter a tunnel with more imps as well as zombies, kill a pinky that charges at you from the other end of the tunnel then punch through another vent to land in a room with more zombies as well as a blue teleporter. Step on the teleporter to enter a room containing a baron of Hell - try to stay out of melee range as much as possible, either by staying on the move or by using ice bombs and faltering weapons to hold it in place. Head up either set of steps and go through the green door at the top to find a runestone, then turn left and go through the circular airlock to get outside.

There is an arena ahead with various heavy demons including an arachnotron, a cyber-mancubus and some carcasses; once they are defeated, continue moving forward up some steps and kill several blaster soldiers that come through a door, then go up the slope to a second arena where you will find a pain elemental that throws lost souls at you; once the elemental is killed it will be replaced with a dread knight and then a Doom hunter, so use caution. Once the arena is clear, drop down the hatch that rises from a square platform then look down to see a circular opening in the middle of a fan that you can use to get inside the BFG core. Punch the cracked fuse in front of you to lower the energy grids then walk straight through a small opening in the wall behind it to enter a room full of pistons; kill the zombies and gargoyles here, use the automap station then climb on top of the pistons to reach a vent leading out of the room. Exit the vent and turn right to follow a passage with flame jets, kill a mancubus coming the other way (along with a prowler that tries to surprise you from behind), then use the ladder at the end of the passage to reach the BFG-10000.

To the core

After the cutscene, go through the door in front of you and use your new BFG-9000 to kill all the zombies and cacodemons ahead, then step into the open blue teleporter to go down to the destroyed Mars facility. Follow the platforms down until you reach the facility entrance then head straight forward to a door, through which you will see a large ion catapult; do not look at it for too long, as there is a combat arena below you with a buff totem - drop into the arena, turn left and head towards a launcher then look right to find the totem; once the totem is destroyed you can turn your attention to the other enemies, which start with a Hell knight and carcass and end with a mancubus and two whiplashes. After clearing the area, go down the hatch that opens under the center platform then head through a doorway and go straight forward until you get to an airlock with an elevator behind it. Ride the elevator up to a room containing the ion catapult's control panel and interact with it, go through the previously-locked door to an airlock with another runestone behind it (this should be the final rune you acquire), then continue on to the catapult and use it to fire yourself to a building on a nearby meteor.

Kill the soldiers and mecha zombies ahead then go up the steps and turn left to enter a room with several tentacle holes; tread carefully as most of them contain tentacles. Look for a box under an open vent and climb up it until you reach a Night Sentinel spirit holding a Praetor suit point, turn left and jump across to a launcher that will fire you up to an overhead ledge, then drop down the other side to land on a rock platform. The path ahead leads past a number of small generators that produce harmful electric fields, so avoid walking on them as you continue down to a platform with a couple of imps on it. Go down the steps here to find a climbable wall and go down it as far as you can, then turn around to leap to a launcher that will blast you up to a small rock platform; from here you need to turn round and time a leap past some spinning debris to reach the tunnel behind it. Go through the tunnel and kill two cacodemons that fly towards you, then jump down and dash towards a large building where some mecha zombies are shooting at you. Two barons will spawn as soon as you land, but there is a unit of BFG ammo on the upper floor that you can use if needed.

Once the barons and other enemies are dead, go through the large door on the lower floor and walk past a pair of moving lasers - a pain elemental will crash through the ceiling and it will be joined by several gargoyles, so kill them all to open the next door and go outside to dispose of two cacodemons. Make your way down to a large platform with a rotating tower and kill all the enemies there (including another baron), then continue onwards and downwards to a large platform that has a ledge with several zombies running round it. Head round this ledge to see a couple of climbable walls (the right-hand one is faster, but the one between the columns can lead you to an extra life) and go up to a platform with some more demons, then make your way to the top floor and use a launcher to fire yourself over to a large building. You will see a wall explode as you land on the walkway - jump across to this wall to find an airlock leading inside the building, then go through and clear the next room of tentacles before dealing with a revenant and Hell knight that enter the area.

Head through the tentacle area until you get to a room full of barrels and boxes, then drop down the hatch here and head forward to find the escape pods - the green-lit pod can be used to get yourself down to Mars. After the cutscene, follow the path down into a stone ruin and punch through a green-cracked wall to enter the final arena - you will have to contend with various Hell nobles followed by an arachnotron and then a Doom hunter. Once all significant opposition has been destroyed the gate at the back of the arena will open - go through it and use the BFG ammo provided to blast any remaining opposition, then cross the platforms until you reach a launcher leading up to the slipgate for Sentinel Prime.

Slayer Gate

In the final building of the meteor section are several rooms with tentacle holes. One of these rooms has some steps leading up to a computer terminal with a distinctive orange button; press it and look through the window ahead to see a wall support move, then go round to that area to find that a block has risen letting you get up to two cracked vents. One of the vents has the "QUAKE CHAMPIONS - Goroth" album behind it, while the other leads to the Slayer Key. As soon as you get the key, drop down and turn left, go forward round a corner then turn right to find the Slayer Gate.

This encounter initially pits you against a marauder along with prowlers and various fodder demons, including a Maykr drone - drones can be quickly killed with headshots from the heavy cannon's Precision Bolt or the combat shotgun's Sticky Bomb, but make the marauder your priority due to its strength. Once the marauder is killed, it will be replaced with four Hell knights followed by two barons.

Challenges

• Big Ba-da Boom - Kill 40 demons with a very big gun
• Disarmament - Destroy three arm cannon weak points on mancubi
• Lock and Key - Find the Slayer Key

Secret encounters

1. A gore nest can be found in the same area as the second Praetor suit point. You will have 25 seconds to kill a revenant, a spectre and some fodder demons.
2. After jumping over the room full of tentacle holes and landing on a rock ledge on the other side, head round the building in front of you to go inside it and find a cracked grate hiding a blue teleporter - step on the teleporter to reach a gore nest. You will have 30 seconds to kill several imps along with two whiplashes, a cacodemon and a prowler.

Special items

• Six extra lives
  1. A 1UP can be found above a bottomless drop in the first outdoor arena.
  2. As soon as you enter the Mars facility building, turn right and follow the passage to a 1UP.
  3. From the third Praetor suit point you will use a launcher to jump to an overhead ledge. There is a monkey bar above this ledge, and if you swing off it you can dash forward to a cracked wall hiding a 1UP. (If you miss it, you will drop into this room after leaving the second secret encounter.)
  4. In the middle of the meteor section is a tower with two rotating fins, which has the 1UP on it. Just before reaching this tower you can use a platform with a launcher to fire yourself across to a second platform with an electric generator, then make a carefully-timed jump past the fins to reach the pickup.
  5. From the platform with the third BFG ammo pickup, drop down to a ledge with zombies and follow it round until you see a climbable wall between two metal columns. Jump to that wall, turn left to reach a second wall then turn right to reach a 1UP beside a third wall.
  6. The last 1UP is above the final arena before the slipgate, reachable using a floating monkey bar
• Four Argent cells
  1. In the outdoor area immediately after acquiring the BFG.
  2. On the upper level of the arena where you face two barons.
  3. Just after the tower with the fourth extra life are some floating rock columns that have climbable walls on them. Head along the walls until you see a platform on your left holding the ammo pickup, which is surrounded by electric generators.
  4. Just before the slipgate.

Collectibles

• One Sentinel crystal
  1. As soon as you reach the large building at the end of the meteor section, go through the doorway closest to you to find the crystal.
• Five Praetor suit points
  1. In the BFG core, a Night Sentinel spirit can be found on the upper level of the piston room, in the opposite corner from the exit vent.
  2. After clearing the arena that had the first buff totem, drop down the hatch in the floor then look for a cracked wall in one corner. Punch through this wall and drop down to a platform below you, then go up some steps to a Night Sentinel.
  3. A Night Sentinel is encountered after climbing to the platform above the room full of tentacle holes.
  4. From the third BFG ammo pickup, look back the way you came to see a rock column with a large climbable wall on it. Go up this wall to get on the column (watching out for an electric generator), then jump across to a platform with a medikit before leaping to another platform with a Night Sentinel.
  5. Just before reaching the final arena before the slipgate you have to punch through a cracked wall. Ignore that wall for now and turn left to find a Night Sentinel in an alcove.
• Two Codex pages
  1. "BFG-10000" - as soon as you exit the vent leading out of the piston room in the BFG core, turn left to find this page.
  2. "The Lost City of Hebeth" - on the path leading to the final arena before the slipgate.
• Three Sentinel batteries
  1. After dropping down the hatch leading to the BFG core, turn round to see a battery in the distance which you can reach by jumping over a couple of platforms.
  2. After launching yourself to the large building at the end of the meteor section, turn round to see two round platforms leading back to the area you just came from. Jump across both platforms to reach a T-shaped walkway with a battery.
  3. After using the escape pod, drop down a ledge then turn right to find a battery.
• Two runes
  1. A runestone can be found behind the exit from the room where you encounter the first baron.
  2. A runestone is placed on the bridge leading to the ion catapult.
• One Empyrean Key
• Three toys
  1. "Prowler" - when you reach the room with the ion catapult's control panel, go through the doorway opposite the panel to find a question mark.
  2. "Carcass" - from the second secret encounter, launch yourself up to the floor above to find a question mark guarded by a zombie cultist.
  3. "Pinky" - after dropping down the hole leading to the escape pod room, turn left to see a cracked grate and punch through it, then use a launcher to propel yourself up to a locked room with zombies guarding a question mark.
• One cheat codes
  1. "Onslaught" - as soon as you enter the meteor section of the level, go down the gap in the floor next to the staircase then head forward to a launcher next to a tentacle hole. Use the launcher to fire yourself to the floor above and turn round to find a question mark.
• Two albums
  1. "DOOM 64 - Intro" - From the third Praetor suit point you will use a launcher to jump to an overhead ledge. Turn round when you land on this ledge to see a question mark that can be reached using the monkey bar in front of you.
  2. "QUAKE CHAMPIONS - Goroth" - Follow the directions above to get the Slayer Key. One of the two cracked vents you can jump to has a question mark behind it.

Master Level

Essentials

The BFG-10000

Once the elevator reaches its destination, step out and turn left to see some shield zombies behind a laser. Step past the laser to dispose of a mancubus and more soldiers, then go up the steps and look up to see a vent opening with more lasers; time your jump into the opening then follow the vent to a grate which you can punch through to enter a tunnel that contains zombies, an arachnotron and some carcasses. Follow the path to a circular section to find a blood punch pickup; be ready to use it along with the ice bomb and frag grenade as four cyber-mancubi will appear in sequence. Continue following the tunnel to a second vent opening which will be covered by a Hell barrier as you approach - you will then have to face two arch-viles that appear one after the other at either end of the passage, so avoid letting them summon reinforcements if possible. Once the tunnel is clear, enter the next vent and punch through a grate to land in a room with wandering cueballs; use them to blow up the Hell knights and revenants that appear then step on the blue teleporter to move to the next area.

Get ready to move as soon as you reach the next room - the floor is electrified and four mancubi will teleport in, so push past them to reach the doorway on your right where you can fight them more easily. Once the room is clear kill a dread knight and some spectres that burst through a door, then head straight through it past a "Yellow Access" door to find a passage leading to the yellow keycard. Kill the tyrant that appears behind you then go back to the Yellow Access door you just passed and head through it to find a spirit armor, then turn left to enter a circular airlock - the doors to the airlock will seal once you are inside, purple goo will cover the floor and fast-moving lasers will start moving across the walls. Quickly kill the Hell knight and baron that appear in front of and behind you respectively, then head through the next door to get outside to an arena that contains some blood punch pickups, which you will need to defeat a gang of pinkies that teleport in along with overhead revenants. These will be followed by imps, shield soldiers and cacodemons; after disposing of them, destroy a buff totem that appears on one of the raised platforms before dealing with two tyrants and two pain elementals that join the fray.

Once the arena is clear, a door will open at the opposite side of the arena - go through it and turn left to see some cyber-mancubi and revenants firing at you, then head up the slope to enter a second arena that initially contains imps and revenants who will be followed by arachnotrons, two arch-viles that spawn one after the other as well as dread knights, carcasses and a baron; save the Onslaught powerup above the arena until you really need it. Once the arena is clear, drop down the hatch that rises from a square platform and turn round to see two pain elementals heading your way who are backed up by an arachnotron and two carcasses, then look towards the large circular fan and drop down to an opening in the middle of it that leads to the BFG core. Punch the cracked fuse in front of you to lower the energy grids then push past two plasma turrets and some lost souls to enter a room with pistons where you will face one Doom hunter followed by two more, as well as a respawning prowler; clear the room then climb on top of the pistons to reach a vent leading into a tunnel with flame jets. Follow the tunnel up some steps until you reach a ladder which will be obstructed by a Hell barrier; you will then have to head back down past some empowered demons to reach a buff totem in purple goo. After killing the enemies, including a Hell knight and a cyber-mancubus, go back to the ladder and use it to reach the BFG-10000.

To the core

After the cutscene, go through the door in front of you and use your new BFG-9000 to help defeat several waves of enemies - cacodemons, Hell knights, arachnotrons then more cacodemons along with a Doom hunter and two tyrants (the Argent cell in this arena respawns to help you) - then step into the open blue teleporter to go down to the destroyed Mars facility. Look down at the next platform to see a cyber-mancubus firing bile at you, then go down there before dashing to a second platform with an arachnotron which will be followed by a baron and three cacodemons. Continue on to the facility to find that your route is blocked by a laser grid - turn right to find a power switch and kill the mancubus and blaster soldiers that teleport in to defend it, then pull the switch and return to the now-deactivated laser grid to dispose of a Hell knight and some zombies. Follow the passage to a "Blue Access" door and pull a second power switch next to it, then go back the way you came to kill some whiplash spectres that have arrived. Go back to the first power switch to kill a waiting arachnotron, then step past the now-deactivated laser grid behind it to reach the blue keycard.

Kill some spectres on your way back to the Blue Access door and go through it to see an ion catapult ahead, then drop off the platform to an arena that initially contains imps and mecha zombies followed by shield soldiers, revenants, two barons and two pain elementals; once they are defeated you will have to contend with two marauders and a cyber-mancubus, as well as Hell knights and whiplashes that will keep respawning until the marauders are dead. After clearing the area, go down the hatch that opens under the center platform and approach the cracked wall next to the laser grid, defeat a cacodemon that bursts through it then drop through the wall to a tunnel below where you will find a mancubus and two carcasses waiting up some stairs. Turn left at the top of the stairs and go through a door to clear out two shield soldiers followed by two dread knights then follow the passage to an airlock with an elevator behind it. Ride the elevator up to a room containing the ion catapult's control panel and interact with it, go through the previously-locked door to an airlock then continue on to the catapult and interact with its controls to fire yourself to a building on a nearby meteor.

Get ready to move once you enter the building, as when you start moving a buff totem will appear nearby and you will have to fight past empowered mancubi and gargoyles to reach it. Go up the steps and head through the left doorway then turn right to enter a room with tentacle holes (they do not contain tentacles). Turn left and look for a box under an open vent then climb it to an overhead platform and turn left to see the buff totem on a ledge on the other side of the room. Jump over to the totem to destroy it then use the launcher to propel yourself over a wall and land on a rock platform below. The path ahead leads past a number of small generators that produce harmful electric fields, so avoid walking on them as you continue down past some arachnotrons to a platform with some rock steps on it. Go down the steps to find a climbable wall and head down it as far as you can, then turn around to leap to a launcher that will blast you up to a small rock platform; from here you need to turn round, slay four cacodemons that appear behind you and time a leap past some spinning debris to reach the tunnel behind it. Go through the tunnel and kill two cyber-mancubi that appear, then head past the electric generators and dash down to a large building where five arachnotrons are shooting at you. When you land you will also have to contend with one Doom hunter and two pain elementals, followed by one pain elemental and two Doom hunters.

Once all the enemies are dead, go through the large door on the lower floor to a seemingly empty room that will fill with fog; you will then have to contend with whiplash spectres and a crowd of cacodemons, and once they are dead the floor will be covered in purple goo and you will be pitted against two barons and a tyrant; use the super shotgun's meat hook to get around more easily. Once the fog clears and the next door opens, head through it and make your way down to a large platform where a arachnotron, cyber-mancubus and dread knight are firing at you, then continue on past some climbable walls and look down to see carcasses and a revenant shooting at you from a ledge below; jump down to this ledge then follow the path beneath it round to another couple of climbable walls (the right-hand one is faster, but the one between the columns can lead you to an extra life) and go up to a platform that initially has gargoyles, imps, blaster soldiers and mancubi on it; once they are defeated a buff totem will appear on the top floor, so go up there quickly to destroy it and get rid of the enemies that have respawned and been joined by two pain elementals.

Once the platform is clear, a launcher will activate on the top floor; use it to fire yourself over to a large building. You will see a wall explode as you land on the walkway - jump across to this wall to find an airlock leading inside the building, then go through to a room with tentacle holes (which are again empty) and get ready to face a gang of Hell knights that approach from multiple directions followed by whiplashes, carcasses and pinkies. Head through the tentacle area until you get to a room full of barrels and boxes, then drop down the hatch here and head forward to a room containing several plasma cells then turn left to approach the escape pod area; it will be sealed with a Hell barrier as you approach, and you will have to contend with a large number of shield soldiers - liberal use of the plasma rifle is recommended. Once the barrier drops, use the green-lit escape pod on the right side to get yourself down to Mars.

After the cutscene, follow the path down into a stone ruin and punch through a green-cracked wall to enter the final arena - you will initially face two tyrants that spawn at the back of the arena joined by cyber-mancubi, then two Doom hunters backed up by Hell knights and carcasses. After eliminating the hunters a buff totem inside a shield dome will appear at the back of the arena; defeat the cyber-mancubi and other heavy demons that spawn around the totem to make it vulnerable, then get ready to face a large contingent of barons, Hell knights, pain elementals and arachnotrons followed by three tyrants along with some whiplashes and cacodemons. When you finally win the battle, the gate at the back of the arena will open - use the Argent cell behind it to clear the final wave of opposition, including two tyrants waiting by the slipgate, then cross the platforms until you reach a launcher that will send you up to your destination.

Weapons

In Classic Mode, the weapons and their mods are hidden in the following locations (note that mods do not appear until you collect their corresponding weapon):

• Combat shotgun - available from the start.
  • Full Auto - in the vent just after the start of the level.
  • Sticky Bombs - turn right after finding the first spirit armor to see this mod.
• Plasma rifle - available from the start.
  • Heat Blast - at the entrance to the second vent
  • Microwave Beam - in the booth where you found the Sentinel crystal.
• Rocket launcher - after using the blue teleporter near the start, go through the doorway on your right to find this weapon.
  • Lock-On Burst - found as soon as you enter the destroyed Mars facility.
  • Remote Detonate - by the green-cracked wall leading to the final arena.
• Heavy cannon - after clearing the first outdoor arena, a door will open; this weapon is behind that door.
  • Precision Bolt - on the platform that held the first Praetor suit point.
  • Micro Missiles - at the base of the tower holding the fourth extra life.
• BFG-9000 - automatically collected from the BFG-10000 control pod, just like in the standard level.
• Ballista - found in front of you after using the blue teleporter past the BFG.
  • Destroyer Blade - before the ion catapult.
  • Arbalest - in the vent leading to the third soulsphere.
• Super shotgun - in the area where you found the prowler toy.
• Chaingun - in front of you as soon as you enter the starting building in the meteor section.
  • Mobile Turret - inside the large building in the middle of the meteor section.
  • Energy Shield - at the bottom of the hole leading to the escape pod area.
• Crucible - above the room that held the second secret encounter. You will have to get past several mancubi and other enemies to reach it.

Special items

• Six extra lives
  1. A 1UP can be found above a bottomless drop in the first outdoor arena.
  2. A 1UP is located by the blue keycard.
  3. From the third Praetor suit point you will use a launcher to jump to an overhead ledge. There is a monkey bar above this ledge, and if you swing off it you can dash forward to a cracked wall hiding a 1UP. (If you miss it, you will drop into this room after finding the second soulsphere.)
  4. In the middle of the meteor section is a tower with two rotating fins, which has the 1UP on it. Just before reaching this tower you can use a platform with a launcher to fire yourself across to a second platform with an electric generator, then make a carefully-timed jump past the fins to reach the pickup.
  5. From the platform with the third BFG ammo pickup, drop down to a ledge with zombies and follow it round until you see a climbable wall between two metal columns. Jump to that wall, turn left to reach a second wall then turn right to reach a 1UP beside a third wall.
  6. The last 1UP is above the final arena before the slipgate, reachable using a floating monkey bar.
• Five spirit armors
  1. In the chamber that held the first runestone.
  2. On the platform that held the first Sentinel battery.
  3. In the area where you found the prowler toy.
  4. In the booth where you found the Sentinel crystal; taking it causes a Hell knight to appear outside.
  5. In the vent that held the "QUAKE CHAMPIONS - Goroth" album.
• Three soulspheres
  1. After using the blue teleporter near the start, go through the doorway on your right then turn right and follow the passage to a dead-end.
  2. Above the room that held the second secret encounter. You will have to get past several mancubi and other enemies to reach it.
  3. In the vent that held the Slayer Key.
• Five Argent cells
  1. In the outdoor area immediately after acquiring the BFG (this pickup respawns).
  2. On the upper level of the arena in the middle of the meteor section, where you face Doom hunters and pain elementals.
  3. Just after the tower with the fourth extra life are some floating rock columns that have climbable walls on them. Head along the walls until you see a platform on your left holding the ammo pickup, which is surrounded by electric generators.
  4. Under a ledge on the right-hand side of the final arena before the slipgate.
  5. Just before the slipgate.
• One Crucible charge
  1. In the alcove that held the fifth Praetor suit point.