I think that daily challenges should reward you with gold.
Im trying to get that cool guy Orochi the samurai hero,but 70k I mean come on I've been playing for ages now best I could get in one go was 789combo and 990 gold (even I was surprised that I got this far) it's just way too expensive.same goes for the upgrades,it's fun yeah but do you really need to go that far for a dude running on your screen for HOURS give the guy some money... he deserves it.
Awesome!! only thing thats gonna make this game better is...MORE FREAKING UPGRADES!!! once you eat them all you grow a little and that's as far as it goes.