Solid start, but needs work.
There is a great platform here to build from, but it needs some work. The game's difficulty ramped up nicely, but some weapon balancing is in order. I like the flamethrower, but the shotgun and machine needed to be more powerful. The bosses were cheap, with attacks you couldn't do anything about, like guns. I got to the end-ish, but I didn't know where to go after that, and I died after running out of time. It wasn't clear what I was supposed to do. The game also starts to lag heavy near the end when all the enemies are activated, but at least the lag works in the player's favor. The levels got very tedious with having to trek through section by section of levels you've already cleared. If you work on the weapon and level design a bit, and make the gameplay objectives a little more clear, your next game could kick ass.