That's correct, as enemies were not implemented on stage 3 deadline. It was written in the README file
oops, missed it because it didn't have the .txt extension

I'm not sure what do you mean by "queasy"... Can you explain it in more detail ? There was no "head bobbing" effect in stage 3 version (it's done in stage 4 version), does this fix / improve the issue ?
I mean it made me kinda sick (well not that bad), I'm not sure head bobbing has anything to do with it, probably more something with the viewing angle (FOV). So far all FPS and 3d games I've encountered gave me no trouble sitting through multi-hours sessions, but there was one that had the same queasy-inducing effect: HalfLife 2 - you're in good company
I could barely stand watching the HL2 screen in more than 5-10 minutes sessions, and actually abandonned the game by the time you reach the base after the canals (walking in the interiors became just too much).
I later found other many people had the same issue and that there were unofficial FOV patches circling the forums, though I never resumed playing the game with it (and don't have the game anymore).