Waaay too easy, although some levels are much harder than others, weird difficulty curve. Going around and collecting all pickups is just annoying, and like others said the game seems just too grindy.
Was going to give 4/5 but because of that annoying link on the lower left, which is IMPOSSIBLE not to click many times by accident its 2/5. I understand that developer want to make money of this game, but this is just not cool.
Yeah, this is a known issue (check forum). We're working on a fix. Sorry for the inconvenience.