It's been 2 hours?!
Jesus, I lost several hours in this, time flys when you're having fun!
Great weapons, amazing animation, badass sounds, and truly EPIC music.
The only improvement I can think of is expanding the upgrades and the number of enemies in the wave mode. I found myself running around trying to find the last few guys, rather than them trying to tear my guts out.
Still, this is a wicked sick game. Fav'd.