Cool sorta voxel rendition of the older FPS style.  Movement and weapons were fast and responsive.  Nice variety of weapons, although I think the shotgun could have used a wider spread.  Levels were a bit simplistic, the lab was the first that started to feel like I could explore, and did  a good job of hinting there was more to it than what is right in front of you.  I would liked to see some different enemy ai, the same strat worked against every encounter basically.  I did encounter 2 glitches, 1st: in the first room you encounter the flying bombs with the long walkways on either side of the room, I would get stuck bouncing if I tried to walk off them without jumping.  2nd: versus the big robot, I ran out of ammo so I quit the level and restarted the run and when I got back the ground was very shiny/washed out, and there were 2 robots (I suspect the light sources were doubled).  I think this is a good foundation for an FPS with some more balancing/variety and has alot of potential for interesting level designs (adding couching opens up lots of potential secrets!).

As someone who has made a retro FPS of my own, I loved seeing this updated spin on those old-school games. Everything looked awesome and was fun to explore. Loved the weapon and enemy variety. Really good level design, too. Good luck on finishing the project! :)