Wait, there's no level select? The Xbox version had it.
Another thing I ran into that kinda pissed me off. The fucking crane game in Alpha Labs Sector 3! Since this is the PC port and not the Xbox version, the controls aren't automatic. So you have to manually move the crane up and down, and manually put the barrels in the chute by yourself. Not only that, but you can't see the crane and the controls at the same time. I almost rage-quit every time the barrel missed the chute, but I got the hang of it.
Another thing I noticed is that the shotgun got nerfed to fucking hell. In the Xbox version in Recruit and Marine, it only took one shell to kill an imp. I don't know if it is any different in the original pc version, but this sucks the hairiest of balls.