It's pretty fun, but it does have its problems. Number one is one that has been mentioned in several other reviews: the difficulty curve. I've noticed the XP you get doesn't match to the total you can earn. As you level up in a game, the monsters drop more XP as you need more, but this game doesn't seem to do that. Not even for the hard levels. Problem two is that you need to clear an OBSCENE amount of sky tower levels to unlock more campaign levels.

it's okay but it's just like every other game like this. Your player only shoots when you're standing still. So you got a million enemies shooting at you and you have to move constantly. Then when their bullets hit you it only takes like two shots to kill you. so of course it's like every other phone game pay to play. and the one thing that I don't get is you can only get hit five times to achieve the star. if you have the shield it blocks it doesn't give you damaged but still counts as a hit??

Been playing for a little over 2 months now, about 30min a day, and so far it's completely f2p with a good bit of content. Lots of "main" game content in terms of stages, harder versions of the same stages, and also hit-less speedrun challenges of those stages. As well as a few weekly rotating events that give you additional items free of charge (Helps alot for early game, as they aren't tied to your progression, you get the same amount as high lvl f2p players if you participate) Very solid game