The progression rate is slow.. Slow as a turtle :P. But anyway, like I said, you hardly progress at all, and all it ever is, is shooting yourself into the sky repeatedly, until you finally save up enough for that new upgrade, then shoot yourself into the sky more. I think, you should add more upgrades, and make some of them cheaper, and add new types of assists (I.E A hang glider, or an anvil to drop down on the bad things or something
 "Toss the Turtle"){kind=icon}