With so many puzzle games on DSiWare already, it's kind of hard to invent a completely new concept for your game. So why not combine the concept of several other games into one?
Shapo is pretty much a combination of Lonpos, Tetris and Art of Balance, with key elements from each coming into play during the game. There's a classic and puzzle mode available to play, though the basic mechanics are the same.
The playing field consists of a large, precariously balanced platform with a hole-filled grid on top of it. Your job is to grab the connected spheres that come by above this grid and drop them on there, trying to fill lines to make them disappear, all the while also making sure to keep the balance. If the platform tips over to the side for too long, the entire grid will slide right off and you will lose.
The tricky part comes from the fact that the spheres you get are of varying weights. There are four different types, and the heaviest is four times as heavy as the lightest, which of course means that if you drop one of the heaviest spheres on one side of the grid, you'll need four lightest ones to balance it out again. The platform tilts rather quickly, so quick thought is required for this: don't just haphazardly throw around spheres to fill up the grid, as you don't want to have to rely on the fairly rare single-sphere pieces to scroll along.
The game's classic mode is a fairly straightforward "quest" of sorts with gradually more difficult levels. It's not an "infinite game" like Tetris, as it's actually divided into stages, and you can quit and continue any time you want.
The puzzle mode is a bit different. It's played on similar grids, but now your objective is to use the (very) limited amount of spheres you get to completely fill the grid. This starts out very simple, with absolutely no need to worry about the weight of the spheres, but as you get further the grids will get bigger and the pieces will scroll by faster, which means you'll need to do some very quick calculating.
The game has fairly forgettably graphics and music. The locations are themed after real-life ruins but don't really look that special. After playing the game we could hardly even remember there was music, it's that hard to notice.
Although not using any individually unique ideas, Shapo's combination of three gameplay features from other titles is unique in its own right. It starts off simple enough, but gets extremely hectic the further you get due to the myriad of things you'll need to keep paying attention to. It doesn't quite have that catchy hook many classic puzzle games have, but it's still a decent title and could be worth checking out if you've got 500 DSi Points to spare.