Best example of a poorly constructed game.
This game has a lot wrong with it. Numerous bugs compound early on to make the game frustratingly hard and then a few levels in, ridiculously easy. Essentially the best tactic for getting all three of the games achievements is to survive to 15,000 points then buy as many upgrades as you can at once. Shortly after unlocking enough achievements you'll become invincible and the real challenge is no longer making it to level 60 but staving off boredom.
This game is a mess and needs a lot of work. Between glitches with the ads, and the game not always letting you restart it makes the whole experience a chore.
And I may be just splitting hairs here by why keep the "enemy power" tally. What difference does it make to me that they'll do more damage when every enemy can kill me in one hit anyway?