BLT

BLT is a single-level PWAD for Doom that was released in 1994. It was designed by Neal Ziring. It was released with Lake4 included as a bonus level.

Secrets

 * 1) After going through the first door, turn left.  Near the candelabra on the south wall is a secret door leading to a chaingun and either a computer area map (on easy skill) or an armor (on medium and hard skills). (sector 20)
 * 2) After pressing the switch in the nukage area in the east, take the teleporter.  Ahead of you is a secret door (marked with a greenish texture) leading to a light amplification visor, a soul sphere and an energy cell pack. (sector 61)
 * 3) After getting the yellow key it is necessary to press a switch at the top of a lift to open the door out of this room.  Pressing the other switch here opens a door to the north, revealing an area with a cage containing several monsters.  The south-west corner of this area contains a secret door leading to two energy cell packs (one on easy skill), and possibly either a BFG9000 (easy skill only) or a stimpack (medium skill only). (sector 100)
 * 4) There is a door at the eastern end of the red key room leading to an imp (two on hard skill), a stimpack, and a teleporter. (sector 131)
 * 5) The teleporter in #4 takes you to an area with a partial invisibility.  There is also a spectre here on medium skill, and two spectres on hard skill. (sector 130)
 * 6) Jump down from #5 into an area with several monsters, a megaarmor and eight armor bonuses. There is a secret door, marked with a darker green texture, in the north-east taking you back to the red key room. (sector 117)

Bugs
The linedefs at the side of the door leading to the blue key room (linedefs 136 and 137) have both been assigned Action 11, meaning that pressing either of them will exit the level.

Current records
The records for the map at the Doomed Speed Demos Archive are:

Things
This level contains the following numbers of things per skill level: