Bio Menace

Bio Menace
Developer: Apogee Software Publisher: Apogee Software Platform: DOS Released internationally: August 3, 1993 This game has debugging material. This game has a hidden level select. This game has anti-piracy features.

Bio Menace is a platforming game based on the Commander Keen 4-6 engine. As CIA agent and mullet connoisseur Snake Logan, your job is to exterminate the hideous mutants that have taken over Metro City and find the man responsible for the attacks.

Debug Mode

Bizarrely, the freeware release of this game enabled a debug mode. Pressing C, O, and D simultaneously will bring up a prompt asking for a command. Enter 91827, then press J, I, M, and Space together to enable the debugging keys:

• F10 + B - Change border color
• F10 + C - Show number of active/inactive objects in the level
• F10 + D - Record a demo
• F10 + E - Skip level
• F10 + G - Activates God Mode
• F10 + I - Free items
• F10 + J - Jump cheat
• F10 + M - Display how much memory is in use
• F10 + N - Turn clipping on and off
• F10 + P - Pause
• F10 + S - Turns on and off slow motion
• F10 + T - Sprite test
• F10 + V - Add Extra VBLs
• F10 + W - Warp to level
• F10 + X - Extra Stuff
• F10 + Y - Reveal hidden areas
• F10 + Z - Lose a life

(Source: Modding Wiki)

Anti-Piracy

The registered version of Bio-Menace uses a simple anti-piracy method that was in common use at Apogee at the time: The game checks for a FILE_ID.DIZ file (commonly used as an archive description on BBSes) that contains the following:

████▓▒░ ALERT THE SYSOP IMMEDIATELY! ░▒▓████
████████████████████████████████████████████
THIS FILE IS NOT SHAREWARE -- it is ILLEGAL
and forbidden to upload this copyrighted
software to bulletin boards. If you see this
message on a BBS, please request that the
Sysop remove this software IMMEDIATELY!!!
█▓▒░ OR CONTACT APOGEE: (214) 278-5655 ░▒▓█
IT IS ILLEGAL TO GET THIS FILE FROM A BBS!
████████████████████████████████████████████

This effectively labels pirated copies of the game on BBSes so that SysOps could quickly remove them. Upon exiting a level, the game will run a checksum on FILE_ID.DIZ. If it doesn't match up with a hardcoded value, the game will display an error message. After it's dismissed, the game will drop back to the title screen.

Amusingly, the freeware release points out and explains this copy-protection measure in its readme file, instead of removing it, "since we're unable to recompile the game to remove the check for that"!

To do: Examine the exact details of how the checksum is, well, checked.