Castle Wolfenstein on the Apple ][. I liked how you were outnumbered, stealing ammo off the bad guys, and saving the day. It was missing just one thing ... zombie nazis. Well, these may not be exactly zombies, but they sure are supernatural nazis. And they still make "aiiieeee" noises when you gun 'em down!
Once I'd popped the disc into the PS3, it didn't come out until I was done with the single-player campaign. It's excellent! There's a goofy story. There are nazis using gateways to other dimensions. There are weapon choices and upgrade choices that let you pick your fighting style. A ton of detail makes it extra compelling. I really enjoyed it!