The feedback during fights and during level transitions is very well done. However the upgrades were more of a mystery to me, or did so little that it was barely noticable. The art was art like I would design it, only a bit better ;P To be honest it looks like placeholders to me, the art could have used some more love but I guess all time went into the (very smooth playing) player controller.
Overall a good little game, just not my cup of tea ;P