Not bad at all...
Well, I'm at level 14 or so, with no signs of stopping, so I thought I'd give a couple tips:
-Like the creator said, get Pickpocket ASAP. Go for armor, sword, and money magnet next (max armor means everything does 1 dmg to you, max sword HEALS you 1 point for each hit you make and cuts through even the toughest goblins in 3 hits) Get HP ups with excess cash, if you feel you need it. Save the HP indicator for last... knowing how much hp a goblin has isn't really that helpful.
-In later levels, it's better to jump-attack through a crowd of goblins, then make them chase you to the other side. If done right, they won't be able to catch you before you can turn and do it again. if there's a new goblin coming ahead of you, just turn and jump-attack through the mob again, or if you have more room ahead, attack the loner. Money Magnet makes sure you don't lose any cash for this.
-Lower the graphics setting to minimum, unless you got a really fast computer. This helps a LOT.
As for the game, it's fun sending hordes of goblins flying around, but it seems some of them have a longer reach than their weapons indicate, so you can end up getting hit even when a goblin pokes thin air. Also, fighting on the ground is near suicide, so the punch/kick button and block buttons are pretty much useless. If you could find a way to make ground combat more meaningful without losing too much challenge, that'd be awesome for the sequal (if you make one).