Throughout the game, you will feel like you never have enough coins for the upgrades you need. You can receive more coins through re-playing stages you've previously beat, but this isn't much fun.

Meltdown seems to have been created with multiplayer in mind. Playing single player seems too hard at parts, and game mechanics sometimes just feel off.

There is no local co-op available to players of the free download. AN IAP will have to be purchased to unlock that functionality.