It is a fun game, no doubt about that. However there are two problems. It does not work on the 360 and the fact that if you do not eject before getting blown up your save game file is erased.

The value is dependent on a few things. Do you have the box? Instructions? Screwdriver? All pieces including the cap that goes over the button (eject I think)? Also, do you have the green or blue button version? The green is worth more.

All things being said you can expect $80+ shipped from a 100% complete copy. I would hold onto it, especially if the rumored Steel Battalion Kinect is real. The value may increase.