Hedgehog Launch is a very simple game -- you have a hedgehog, and using a rubber band launcher, you launch him into the air. While he's in the air, you can maneuver him from side to side using a rocket pack (but you have a limited amount of fuel; once it runs out, you're just dead weight). Your goal is to build a rubber band and launcher so powerful, you can launch your hedgehog into space (where "space" is defined as approximately 4500 feet high). And how do you do that? Well, conveniently, the air into which you're launching the hedgehog isn't like the air around my place -- it's filled with coins which you can collect for money (there are three denominations, 25 cents, 1 dollar, and 5 dollars), and also filled with launchpads which not only give you a cash boost (1, 5, or 10 dollars) but also propel you higher into the air. Your amount of money for a round is determined by the amount of cash collected times a bonus for your highest elevation reached times a bonus for your time of flight. These multiplicative bonuses mean that in later rounds, when your launcher is already pretty good, collecting even a relatively modest amount of money can lead to huge amounts of swag. This money you can use to build various upgrades to your setup; not only can you improve your launcher, but you can fit your hedgehog with a parachute, radar, goggles, or booster rocket, or improve his maneuvering rockets.
Naturally, there's a very strong positive feedback component in the game, in that making money makes making more money easier. And indeed, the one constant complaints in the comments is that reaching space in 5 days (which is the prerequisite for the hard badge) is very heavily dependent on luck on the first day -- if you happen to hit a couple of the yellow 10-dollar launchpads, your odds are a lot better, and (especially on the first day, where you don't have much gear on your hedgehog) whether or not you hit those launchpads is pretty much a matter of luck, since their location is entirely random. This complaint is true; sometimes, especially in the early days, you'll just end up with a terrible launch and end up wasting a day, and there's not much you can do about it other than try again. Still, the game is hardly boring, so as long as you're not worrying too much about the badge, it's not a big deal.
Being a jmtb02 production, the game is very flashy; the sound effects are good, the music is very entertaining and breezy, and the graphics are full of stars and sparkles. Overall, this is a cute little game; because of the randomess, it's not High Strategy or anything like that, but it's an entertaining little diversion for a little while.