There's no polite way to put it: Bloons TD 4 is genuinely unplayable. It's a simplistic tower defense game that doesn't really bring anything new to the table in the first place, but that's not the problem. The problem is that the game regularly overloads itself to the point that it no longer accepts input, a truly game-breaking issue that really should have been addressed in beta testing. A colourful presentation, fun music and unlockable levels and upgrades fail to salvage a game that simply doesn't work in the first place. This is one balloon that's never getting off the ground.