Has more coding bugs than in-game ones.
It's playable. It's kinda fun. It's simple. Nice music (at least in the "shop" - though that's just one track). Nice graphics, as far as I've seen. Varied weapons. And I think this is THE first game I've seen to portray a shotgun correctly, i.e. tight-bound cloud of pellets.
Overall, for a first submission - very good job.
It's damn easy, though. The aliens can barely put a dent in the walls, what with the insane regen rate. Actually, I'm over 20 levels in and they never managed to bring a wall to less than 95%. And why the hell a move option if there's no goddamn reason to move outside of the first few levels to hit multiple targets with a shotgun... even though it's not even necessary to survive?
No weapon hotkeys, though that's barely a problem since you never switch mid-level. No reload button, which is a bit irritating.
And when the hell does the second half of the guns unlock?
The coding... that's where things fail, though.
For starters, the game doesn't detect mouse clicks correctly. There's no way to shoot accurately with single-shot weapons; the game even reacts to mouse button RELEASE instead of press, so you can't even hope to overcome the problem by pushing it longer. The only sensible way to fire is semi-auto: click goddamn fast. And since when is it possible with a shotgun?!
Autofire weapons - ok, less of a problem. Just NEVER, EVER RELEASE THE MOUSE BUTTON. Except with some that spit a lot of bullets, the hit detection just fails. Yes, bullets fly over the monsters without doing anything. Irritating.
Plus, a fun bug: hold the fire button with an autofire weapon once the wave ends. If you're lucky, the reload will kick in the moment the game switches to the shop and the weapon will keep firing while you're there. Once you get back to the game and switch to that weapon, it'll get back to firing without a mouse click. It'll go into negative ammo - I'm guessing it comes from some mirror universe or something ;p - and never need to reload for the whole level. But that's not the best part: you can click and hold the mouse button and the gun fires at TWICE the fire rate. Magical double-gun. Works up to around -500 ammo, I think.
And this, kids, is why you put in redundant failsafes to your code.
Anyway - seen so much worse stuff pass from even big companies that it's not much of a problem. The game gets kinda boring, though, when you have half the weapons unlocked and cash just stacking up without being able to spend it.
Has potential.