The lack of control at restart is frustrating. It would be better if there was a pause when you die (and possibly some kind of animation), then full control when the level restarts.
I was doing fine until level 4. The shaking of the screen makes me motion sick after a couple of tries.
Good game in general, though. It could use a little more visual variety, something to make later levels feel different than earlier levels.
Very repetitive. It needs rounds just so you can take a break every now and then. the controls also feel very mushy, I have trouble getting close enough without running guys over.
Aka, here's how I beat hard. I put half my monkeys on the left side an half on the right. That way each group of monkeys will attack one stream, then attack the other stream after their first stream has mostly passed by. Then I put bomb towers in the middle so that they'll attack both streams at the same time. If any black bloons gets past their initial monkeys, I use spikes on them so that the bomb towers don't waste ammunition blasting something they can't hit. I was able to beat hard without missing any bloons this way.
By the way, the quote at the end of level 40 is incorrect. It says, "Consistency is the hallmark of small minds." What Ralph Waldo Emerson *actually* said was, "a foolish consistency is the hobgoblin of little minds". That's a much better statement, since consistency in itself is not a bad thing.
Yeah, starting over the whole level is just a waste of time. Repeating stuff you've already completed is dull.
The game should also save your progress so you can stop and start again later.