Great looking and feeling game with a somewhat lacking enemy variety and a shotgun with the most pathetic range I've ever seen.
Cool level design that loops on itself and makes you backtrack through the same places while changing their geometry and filling them with enemies again to make it fresh, and somehow never ends up feeling like you're just retreading your steps.
Wish it would be more popular; there are only like three custom campaigns made for the game and one of them is broken due to changes introduced by the 1.0 version.
I should finish it one day.