Ridiculously slow progress. You basically don't improve at all with each upgrade. It really feels like you're trying to force people to buy the currency by hampering progress.
I really want to enjoy this game..... However, controlling the arm get extremely frustrating. Even just on the first level trying to get the crate the right way around I want to scream.
Check the options screen for different themes (none of which I personally created, because I am not a designer)!