It's been a while since I last played this game, but the last time I did play it, I was trying to upgrade all of my weapons and the very last one was the Chimp-O-Matic. It seems that every time it went to the upgrade sequence with this weapon, the game would freeze up and I had to start over with upgrading it. Has anyone else ever experienced this and if so, has anyone ever found a fix for this? Also, could it just be the disc that I have? Please help, and thanks.