Terrascape is another game by NegativeONE, the developer behind Newgrounds Rumble (review here), and the two games share quite a bit of similarity; while Terrascape bills itself as a "Adventure-Platformer-Brawler hybrid", let's just say that as an adventure platformer, it's a very good brawler.
Anyway, so the basic brawling action is pretty much the same as in Newgrounds Rumble -- you move, jump, and have strong and weak attacks; these can be nicely chained into combos, but apparently only in the air. You can also pick up items which give you magic spells. The game offers a couple of modes; there's a couple of variations on straight fighting, and then the story mode, in which you have to battle your way through three different stages to claim an ancient artifact. Each of the stages is quite short and simple, though, so most of the content in story mode is still pretty much beating people up. Most of the rest of story mode consists of falling off platforms and having to start over again, which is kind of annoying. There's also hidden coins in story mode which you can collect to unlock the full power of the artifact; however, when I tried collecting them, it seemed kind of glitchy -- it would sometimes fail to record coins I was sure I had gotten. Some of the coins are also extremely difficult to find -- they require taking a leap of faith off the edge of the screen into areas that aren't automatically revealed by scrolling, which is really annoying.
Overall, the brawling action is solid -- your characters have a variety of moves and the animation is good, but you don't need to be particularly skilled to triumph; since there's not a lot of different things you can do, a pretty straightforward button-mashing strategy can carry you through the game without too much difficulty. The graphics are good; the characters are each well-realized and each of the four different story mode worlds does a good job creating a distinct feeling. The sounds are pretty run-of-the-mill; the music is nicely varied, but does get a little repetitive.
Terrascape isn't a long game -- you can probably complete story mode in 15 minutes or so, simply because there just isn't too much substance there. While the core fighting action is not bad, the adventure components of the game just aren't well-developed enough to be really interesting. Overall, it would probably benefit from a stronger focus on one aspect of the game rather than trying to be several things at once.