Capability to save/reload all your game ( options -> save -> copy paste encoded string into notepad, reload it from anywhere).
Many guns and cool upgrades as soon as you get more XP points ( like in Zelda2, or FF3 ).
Players specs increase as you buy more things into shops ( like in Tonyhawk proskating game ).
Lifes bars appear on top of monsters and player head like in StreetFighter 2
Level editor including along with user community made levels
Music/graphics/level design cool. You can swin you can climb tiled slopes jump shoot run and collect as much gold coins as possible.
Shops and XP mechanism make players comeback to the game.
Grizzly made 10.000.000 hits, a similar game with no guns and not really nice design… hopefuly this one might do even more.
Video of the game : http://fb.me/2YKu2nk