Yes, I wonder if the differentiation between Punch Quest's tepid profit and between TF2 and other successful in-app-purchase games is that Punch Quest is a single-player game with very little social action. It's certainly a high quality game, one of the most polished endless-runner type games I've ever played. But since the game is enjoyable without all the purchasable perks...and because I have no one to brag to/compete with...I don't have much incentive to buy anything. In a sad way, PQ's competence and good faith is the cause of their troubles.

TF2 is surprisingly making a lot of money for its age and niche community (I call it niche because it's tight-dependence towards teamwork makes it unforgiving to newbies who'll get booted)...I don't understand why people buy the hats, but I do think there's an advantage to picking up the special weapons.