Several cheat codes for K240 were known soon after the game's release, with some cheat disks listing four cheat codes and others listing twelve. Disassembly of K240 v2.000 using IRA reveals twelve cheat codes.
A structure at $1d3ee in the main game executable contains a list of twelve pointers which refer to strings of Amiga keyboard scancodes, as with the manual protection codes. Each string ends in $44.
The codes are, in order: SKYSCRAPER, PANEL, NASA, ICEMAN, TRACEY, BJORK, WIDGET, NOISES, LOADSADOSH, ICBM, TELESCOPE and LEMINGS. This appears to confirm that there are no more cheat codes than the twelve already known.
The function of the cheat codes has been observed, but not analyzed in disassembly. See JD's K240 page for the effects of cheat codes.
The code contains three ASCII strings used for the cheat codes:
LAB_0B9F: ;1d479 DC.B "ENTER SHIP 1-8:",0 LAB_0BA0: ;1d489 DC.B "TEST: ENTER SFX A-W:",0 LAB_0BA1: ;1d49e DC.B "TEST: ENTER SPEECH A-U:",0
The CU Amiga K240 demo includes no cheat codes, and does not include the version string or version command. Disassembly fails to find the cheat codes at all. However, screenshots of earlier versions on the back of the game box and in a CU Amiga magazine advertisement suggest that the codes were in the game before the demo version, and were removed for the demo. Screens show asteroids with 4 of each missile (ICBM cheat) and the default button extraction (PANEL cheat).
The following ASCII strings appear in a disassembly of the demo version. It suggests that cheat codes were known internally as "help codes", and that a hotkey (perhaps the help key) originally triggered the requester. In the final game, this message was probably removed to avoid tipping off players about the cheat function.
LAB_081B: ; 0000 ; "ENTER HELP CODE:" ; "ENTER SHIP 1-7:" ; "ENTER SFX A-Z:" DC.L $0000454e,$54455220,$48454c50,$20434f44 ;121b4 DC.L $453a0045,$4e544552,$20534849,$5020312d DC.L $373a0045,$4e544552,$20534658,$20412d5a DC.L $3a000000,$ffffff00 DS.L 1 DC.L $30313233,$34353637,$38394142,$43444546 DC.L $00007265
Only seven ships are listed, where the full game has 8. There are 26 sound effects listed (A-Z), where the full game has 23 (A-W). The codes for voice are removed, suggesting that either this feature was added later or it was removed for the demo.
As the message strings have no labels in the demo, it's possible that there originally was a part of the program referring to the strings, and this code was removed for the demo release.