Fantastic as usual, Xaser.
The font is a little unreadable due to how thin it is, even with hud_scale 1, but that's negated by the bars (with health and armor), and the larger font used in the shop menu (for money).
I actually managed to play through Doom 2 with this. Usually I get bored and go "Eh, screw this." somewhere around The Factory.

My only real complaints are that it's kind of rough starting off, and the amount of money you get from bosses (and higher-tier enemies in general) is rather underwhelming. 150 from a Cyberdemon seems kind of low, considering that most upgrades cost over 1000, and you're going to need a few in order to take down a Cyberdemon in a reasonable amount of time. Either that or spend money on offensive powerups, but then you'd be losing money anyway.
Also it'd be cool if it showed how many shots were left in the Needlegun.
At any rate, though, it's a blast. In more ways than one. :3