Fun, but limited
A decent game but it doesn't take long to get all the upgrades and simply continue buying nothing new except a health refill every two levels or so.
The graphics and gameplay are good but later on it simply comes down to how fast you can click the mouse. (A rapid fire upgrade would be nice)
One thing I quickly noticed was that a few enemies shoot a split second after they appear giving you no time to shoot them before being hit.
Overall a decent, but quickly repetitive game.