The first boss is hard. I beat less than a second before my main turret exploded. The bombs dropped, boss blew up, turret blew up, won the level. Good game. Repetitive, yes, but fun. 4/5
Easiest, and only, "impossible" badge I ever got. 186.36 seconds on keyboard mode, and 179.31 seconds on mouce mode. (To do "e", get through it slowly and carefully, aim for 60 seconds, then go fast on all the other levels to make up for it.)
On level 13, just fire constantly. Where the shooting streem starts is where your cursor is and all attacks are drawn to the X, so wait untill the enemy is close to it. I beat all leves already except 51, but I can do it.
8254!!! WOW! My bubble took up almost the entire screen! Lucky with avoud mines, bubbles only, invincibility, and minesweeper. Found an ultimate bullet time too. Hidden power up?
In my opinion: The easiest way to deal 500+ damadge is to equip CRUSHING items. Each adds 100 to 300 extra damadge. With 4, that is a minimum of 400 damadge plus the weapon! With that, I was able to deal over 1000 damadge.