I've been addicted to this game for the last 3 days. Those 3 days have also been some of the most productive days of my life because I can walk away from the computer and it keeps going. You deserve an award for tricking us into being a more productive society...
Enjoyable game, but requires too much repetitive farming for money to upgrade. I would also suggest changing the 15th level a bit. The massive barrage of missiles is nearly impossible to dodge, followed by an insane shower of bullets. 3/5 overall. 4/5 if the farming was reduced. 5/5 if the final boss didn't take me 50 attempts.
 "Battle without End"){kind=icon}
 "Reactance"){kind=icon}
 "Gravitee 2"){kind=icon}
 "Endless Zombie Rampage 2"){kind=icon}