Missing explosions, shrapnel, missiles, a store to buy more options ... just increasing the number of required hits is not much of an incentive to keep on playing. As of now it is more or less pure luck based klicking.
The upgrade system is not well balanced. In fact I don't see a lot of effect. Don't invest into 5 an 10 coins, wait for the 25 to open up. Found the Santa to be a bit unresponsive to the mouse.
 "loops of zen"){kind=icon}
 "Boomshine"){kind=icon}
 "Vertical Drop Heroes"){kind=icon}
 "The Adventures of Red"){kind=icon}
 "SHIFT 2"){kind=icon}
 "Escape the Red Giant"){kind=icon}
 "Ubooly & Friends"){kind=icon}
 "Vox Populi, Vox Dei(a werewolf thriller)"){kind=icon}
 "Effing Worms - Xmas"){kind=icon}
 "Rocket Santa 2"){kind=icon}
 "Not To Scale"){kind=icon}
 "Tactical Assassin 2"){kind=icon}
 "Death Vegas"){kind=icon}
 "Jacksmith"){kind=icon}
 "Lucky Tower 2"){kind=icon}
 "Papa's Burgeria"){kind=icon}
Go out there and get yourself some badges, son! ;)