I realize this isn't primarily a gameplay forum, but I'm stumped: has anyone else encountered a locked EXIT door at the end of the Weapons Factory level, after charging the Maser? I can't help but think it might be a bug in this version...
See attached screenshot.

Something similar has just happened to me. I went through the 'hard hat' door to the conveyors and then decided to go explore the other route, and when I came back the hard hat door was locked! I searched for a noclip cheat in vain, so it looks like I'll have to load my only other save right before the start of the weapons factory...
Would've been nice if GoG could have gotten the source code for this game, seeing as it's a bloody mess. I can't even fathom how Interplay would have tested the game without implementing a noclip cheat... unless of course, they didn't.