i don't know wat grind means, but if it means challenging, i'd say: samurai- way of the warrior (the last boss makes you hold your breath til u kill him!) peggle (praying the ball falls into the bucket) fieldrunners (later stages)
Doesn't "grinding" require a game to have some sort of RPG elements and is all about monotonous/brain-dead leveling (no need to even break a sweat, just takes a lot of time). Right?
