Raiden

RAIDEN.EXE > 0x4AF  90 90 90

A very straight forward word-in-manual check that happens at the beginning of execution.

01ED:00A3       E8F7A8  CALL    FFFFA99D
01ED:00A6       E84EA9  CALL    FFFFA9F7
01ED:00A9       E81FAE  CALL    FFFFAECB
01ED:00AC       E8A793  CALL    FFFF9456
01ED:00AF       E861B2  CALL    FFFFB313

DOSBox Debugger disassembly extract.

Just by stepping over the initial functions, we can tell that the function call @01ED:00AF starts the check, so by NOPing it we just bypass it completely.

The game already works without CD, but you'll be missing the great soundtrack.