So, I've been reminded of this technical bit about the DOS games. There's another thing that might be brought up in a follow-up post, again not about the remaster itself.
The technical bit in question is a bit disappointing: There's nothing new to find in BM's unused GAMEMAPS.* files from the DOS versions. I brought this up in private with the BioMenace Remastered team before the remaster's reveal from last April - I think that's been more than enough time that I may write in public forums now.
For a bit of a background, Keen Dreams and derived games, including Keen 4-6 and BM, made use of variations of the same map format. Such maps could be created using the Tile Editor v5.0 (TED5), written by John Romero. The editor itself was working with files having not much more than RLEW compression. Such files had names like MAPTEMP.BM1. There were further map header files, but I'll skip these for now.
There was also an option to apply another level of compression. While Keen Dreams used Huffman compression, later games like Keen 4-6 made use of a different form, known as Carmack compression:
https://moddingwiki....ack_compression
Applying the extra compression could be done from TED5 itself, starting with the usual MAPTEMP.EXT file and creating a new GAMEMAPS.EXT file. There are again details I'll skip, like the creation of a new map header for a GAMEMAPS.EXT file.
With the version of TED5 distributed by Apogee for ROTT map creation at the time, the menu item "Carmackize maps" should activate that. It's a process that might take a while, especially on vintage hardware.
Now, let's get back to BioMenace. Unlike Keen 4-6, BM as released in the 1990s used the MAPTEMP.* files, not GAMEMAPS.*. Additionally, there were enough files allowing not just the use of TED5, but also the creation of new levels compatible with the existing BM executables.
So, what about these unused GAMEMAPS.* files again? As said, there's nothing new to find. GAMEMAPS.BM3 and the July 1992 beta's GAMEMAPS.BH1 are identical and practically empty. GAMEMAPS.BM1 and GAMEMAPS.BM2 seemed to be partially created from the released MAPTEMP.* files, before aborting the process in the middle.
I tried carmackizing the freeware release's MAPTEMP.* (also matching older versions differing from BH1) with TED5. Outside of bytes no. 8 and 10 (starting from 0), all contents of the unused trimmed GAMEMAPS.* were identical to the new ones created by TED5 as run by me. The reason for bytes 8 and 10 differing seemed to be related to a buffer overread bug in TED5 impacting write of the string TED5v1.0. It's 9-bytes long, including the NUL terminating character, but was copied to a 8-bytes long buffer in TED5's Item_Huffman. strlen was used to calculate the string's length from that buffer. As said earlier, GAMEMAPS.BH1/GAMEMAPS.BM3 is practically empty. Only the TED5v1.0 prefix is present, extended to 11 bytes due to the aforementioned bug.