Frustrating, but fun.
A man by the name of Dr. Cliche (ha!) is attempting to freeze the world with an ice bomb of sorts. His first experiment failed, resulting in the creation of a living ball, which also happens to be the character you play. His second experiment was far more successful, unfortunately, and it's up to you to stop him before it's too late, blah blah blah. Yeah, you're not going to be playing this game for the story. So, what is the game like?
The gameplay involves you traversing the game's world and locating 9 different ball abilities, many of these areas inaccessible without the right ball ability. One of the first things you'll notice is how nicely atmospheric the game's environment is. As the game's title would suggest, it takes place amongst a forest (in the backdrops, anyway), backed up by nicely fitting ambient music. As you're able to travel higher into the game's perpetual night-sky, you'll be greeted by an ocean of stars. Sound relaxing? Don't get your hopes up. If you wish to progress any further in the game, you'll have to endure some very tough challenges, most of these challenges exacerbated by the game's rather awkward controls. You control your ball by moving left and right, of course, and with the S key, you can make the ball go increasingly higher and, with the A key, slow it down or bring it back down from its height immediately. Needless to say, controlling your ball takes some getting used to, since if you don't have a good hold on your ball, he'll bounce uncontrollably around walls and possibly fall into lava, water, or some other similar deathtrap. I never became fully comfortable with the controls myself, since as the obstacles became increasingly more hazardous, I kept succumbing to the ball's irritating tendency to ricochet off the walls and end up killing me. Once you die (and believe me, you WILL die, A LOT), you get sent back to your last save point, with the option of choosing another ball ability if the last one you used did not meet the requirements to get past a certain obstacle (you can also use the space bar to automatically send yourself back if death isn't a viable option). There are moments, during its more frustrating parts, when you probably will wish for save points to appear more frequently, but having since finished it, I realize that they are actually perfectly spaced. A save point will always be around the corner when making it past one of the game's more grueling sections, but aren't so plentiful as to take away from its (high) challenge. The ball abilities you will receive range from the ability to jump slightly higher than the last, to an extremely fragile glass ball that's useful for getting past lasers, to what appears to be a totally useless ball ability that is slower than your default ball ability, and can't jump as high either, but does serve a couple of important uses later in the game. The various environments you will travel to gain these abilities are nicely done, too. These range from a booby-trap filled cave, a mine cart level (seemingly made tounge-in-cheek here...Dr. Cliche isn't the only cliche the game's makers had fun with here), the future (!), and finally, Dr. Cliche's underwater lair. It has to be said, that when you're not yelling at the screen from constant deaths caused by the irritating ball physics, you'll find some truly ingenious level design here. The puzzles, traps...all cleverly and thoughtfully laid out, designed to challenge you, maybe even slam your computer desk every now and then (actually, quite often), but leaving you feeling satisfied in the end for having survived these levels. Overall, this game is an EXCELLENT value. Not only because it's free and takes a very short amount of time to download, but you get quite a game for an already sweet deal. And after you're finished, you can push yourself even further by taking on a speed run, or try to finish it in hard mode. I haven't played it in hard mode yet, but I cannot imagine how they could make this game any more difficult than it already is.
The verdict? Definitely worth a try, for its unique and very challenging gameplay. It's not perfect (I'm still not convinced that ball-shaped characters operating purely on ball physics make for ideal action-adventure game heroes), but it's a very good game.
Oh, and it seems to make a nice companion piece to Knytt as well. In the training area far west, you'll come across Knytt and his little village. Also, the beginning section of the game's "overworld" resembles the general area you start off in in Knytt, mainly the climbable towers you come across.