Strife dead ends
Dead ends are a category of actions that can be taken in Strife which render the rest of the game unplayable. A few of these were intended by the designers, having taken inspiration for Strife's decision trees from early text adventure games which often harshly punish the player with death for making even trivially suboptimal choices. Others are not and are the result of level design or conversation scripting errors. Both types are listed here. Almost all dead ends were repaired in Strife: Veteran Edition through various tweaks and bug fixes, including dynamic protection of NPCs until they have become no longer useful. Most can be re-enabled by use of the port's "classic mode" feature.
Fail Rowan's dialogue
Killing Rowan or choosing any option in his dialogue which causes him to call for the guards will set off the alarm in Tarnhill, as well as make the game unable to progress due to this character holding the Base key needed to meet Macil and receive additional quests. These dead ends are intended. These were removed in Veteran Edition due to requests by the quality control team.
Complete Harris's quest
Completing Harris's quest to steal the offering chalice, or even stealing the chalice without ever speaking to Harris at all, causes Governor Mourel to advance into a conversation state where he will always set off the alarm. This makes it impossible to later obtain the prison pass. This is an intended dead end. In Veteran Edition, stealing the chalice only leads to the player being temporarily arrested, and the governor will return to his normal dialogue sequences afterward.
Offend the rebels
Offending Macil by rejecting his offer to join the Front will result in Macil telling the player to "die in shame and dishonor," after which he sets off the alarm in the Front base, causing everyone to attack the player. The same result can also happen simply by firing any non-stealth weapon inside the base in any area other than the firing range. This is partially intended, although the rebels reacting so violently to accidental weapons fire even after the player has completed several critical missions for them becomes increasingly difficult to believe as the game progresses. This remains true even after the rebels move to their new base in the castle, though there, only Macil will attack the player, while the other rebels will attack Macil. If this is done at any point before Macil is supposed to be attacked, the game cannot be progressed. The offending dialogue choices were removed in Veteran Edition, but it is still possible to anger Macil and the rebels by firing inside either base.
It is possible to kill Governor Mourel at any time, even before meeting him by firing projectiles into his office. This will render progress impossible if done before receiving the prison pass. This is apparently intentional, as Mourel also drops an alarm token object if killed too early, which causes the town to flood with acolytes. Mourel is protected until the prison pass is obtained in Veteran Edition.
Weran has no allowance for being killed early. If he is killed before the guard uniform is returned to him, it will become impossible to complete the sewers and reach the castle gate mechanism. It is unclear if this is intentional. Weran is protected in Veteran Edition until the player is given the flamethrower parts.
Kill the Oracle too early
It is possible to kill the Oracle before accepting his quest to defeat the Bishop. His spectre will attack the player, but cannot be damaged due to the player not possessing enough pieces of the Sigil. It will be impossible to progress any further. It is unclear if this is intentional. In Veteran Edition, the Oracle is protected until the Bishop has been killed.
Kill the Keymaster
Like Weran, the Keymaster has no allowance for being killed early, and does not drop the military ID needed to progress into the Bailey in any of his conversation states. Killing him before obtaining the ID, including by firing projectiles into his area before even meeting him, renders the game unwinnable. He is protected in Veteran Edition until the ID has been acquired.
Leave Administration early
Leaving Administration early without destroying the computer and jumping off the balconies in the Bailey renders further progress in the game impossible due to an accidental combination of two map design issues. Not only does leaving Administration early make it impossible to return directly to that level, but attempting to backtrack to it through the Security Complex will be stymied by a one-way door which shuts behind the player during his first trip through the level and cannot be reopened. This was remedied in Veteran Edition both by addition of a green force field which blocks exit from Administration until the computer has been destroyed, and removal of the unnecessary one-way door in the Security Complex.
Kill both the Oracle and Macil
It is unintentionally possible to kill both the Oracle and Macil during the point in time where the player is supposed to choose in whom he trusts. After telling the Oracle that Macil will die, attacking and killing the Oracle will alert its spectre. Leaving the level at this point through the nearby teleporter will allow the player to return to the Front's base and kill Macil, at which point BlackBird will quip that the Oracle was right and that Richter has taken over the Front. It is then possible to return and kill the Oracle's spectre, after which BlackBird says, "So much for prognostication. Hold it, Macil is calling us back!" At this point, it is impossible to progress further in the game toward either ending. This error is fixed in Veteran Edition with a unique event that only occurs in this circumstance - the Loremaster will intervene, telepathically contacting the player and causing the door to open himself. The player will still only be able to earn the game's middle of the three endings normally, however.
Kill Macil before speaking with Richter
As mentioned in Strife sequence breaks, if Macil is killed immediately after receiving the brass key, the player will acquire the fourth piece of the Sigil, but will find that Richter will no longer converse with him or open the door to the catacombs. This is an unintentional dead end caused by bad coding of Richter's dialogue sequence. It is repaired in Veteran Edition; Richter reacts the same there regardless of whether Macil is alive or not.
Due to failure to tag an intended switch to the proper sector in the Order Commons, it is impossible to progress into the catacombs if Richter is killed before he opens the door for the player. This is an unintended dead end caused by a mapping error. It is repaired in Veteran Edition by protecting Richter until the catacomb key is acquired, as well as with proper tagging of the switch to open the door to the catacombs.
Destroy all ore
If all of the degnin ore in the mines is destroyed before the force fields have been deactivated, it becomes impossible to either free the drones or enter the factory. This is an unintentional dead end caused by the law of unintended consequences - the ore being explosive by necessity leads to it being an expendable resource. This was solved in Veteran Edition with an ore spawner which will add more ore to conveyor belts in the mines and factory levels if it is detected that most of it has been taken or destroyed.