ISO images (really, Alcohol 120% files) of the Dactyl Nightmare SP CD. This was used in Virtuality 2000SU units for an early VR arcade game system.
Requires a 486+, MS-DOS, and a custom video card...
There are a few programs on this CD: the DACC.EXE "Dactyl Nightmare Camera", the SP.EXE "SUPERVISORY PROGRAM" and the ETS.EXE "ENGINEERING TEST SYSTEM".
Notably absent is DAC.EXE, which would be the main Dactyl Nightmare SP game. There's a reason for this: Virtuality games shipped on a combination CD and Floppy, with the CD full of resources and the Floppy containing just game code. This made code updates possible, and also allowed sharing of one resource CD across multiple games.