Pocket Gamer - In-app purchases, eh?
Whether you're a fan of paying to unlock features from within a game or not, there's no doubt that this payment model needs to be carefully employed so that it doesn't become intrusive or break the immersion.
Take Hungry Giraffe. On PSP it was a wonderful eat-'em-up. On PS Vita it's drowning in pleas for cash, and the main spectacle is completely destroyed as a result. 5/10