The iOS port of the PC version of Magicka has gone free for the first time!
http://appshopper.com/games/magicka
I bought it on day one for $2 but did not regret it.
Those don't have it already should definitely pick it up!
(IAPs definitely aren't required to advance, it's all about skill. In fact, some IAPs actually make you more susceptible to damage since this game is very balanced.)
I have no idea what this game is but if the developers of this game believed it was necessary to port the game over to iOS from the PC, then it must be worth a try.
Thanks OP.