Yeah, they're Quake II figures.
The dog-like creature is a Parasite, a Strogg (the evil alien race in the game, similar to Star Trek's Borg) dog-like cyborg. In the actual game, only their head is flesh, Resaurus made them look a lot cooler. The figure is supposed to have a bendy tentacle that attaches between its shoulders, in the game, it latches onto you and drains your life. This figure came packed with Jungle Marine Athena, as others have mentioned.
The head inside the machine is a Strogg Technician. In the game, they just float around in the air and shoot lasers at you. Looks like you're missing some of the little arms that attach to it as well as the back window. That figure comes packed with the Strogg Iron Maiden.
The big guy on the back of the package is a Strogg Tank--really slow, but can take a ton of hits and dish out all kinds of nasty damage with rockets, a machine gun, and a laser blaster. The thing I love about that toy is that the missile rack "tracks" when you turn the Tank's head--awesome! The springy piston legs are cool, but they have a tendency to break, due to the weight of the figure. The Tank is the only Quake II figure that doesn't come with a smaller figure, probably because it didn't cost out due to his size.
Here's a web page I made a long time ago giving some details about the toy line (pictures are kinda crappy though):http://kramwartap.fortunecity.com/index.html