Amberial is a very minimalist platformer which is elegantly executed, but which is relatively short and simple. You'll enjoy it, but there's not quite enough depth to make it feel like a truly engaging game.
Amberial veers from the normal platformer conventions by eliminating something which is normally a staple of the genre: the jump. In Amberial, you control a ball, and all you can do is roll left or right, so handling the vertical dimension becomes much more tricky than in your conventional platformer. Naturally, there's a wide array of springs and trampolines so that you're not always headed downward, but it does add an interesting constraint to the game. You have to reach the exit while avoiding your normal array of hazards -- spikes, moving balls, lasers, and so forth.
Each level features a normal exit and an Ace, which is supposed to be harder than the normal exit but is often as easy, if not easier than, the regular exit. Collecting all the Aces will give you a badge. Some levels require you to press a switch to make the exit appear, and others have a switch for the Ace, which adds a bit of difficulty. Still, the levels tend to be pretty straightforward. There are 12 levels, which form a sequence with several branches, so you don't have to do all of the levels to reach the end, but as none of them is particularly difficult, there's no real reason not to do them all. There's also three bonus levels, accessible by collecting Aces; the last bonus level is not an easy one, especially to get the Ace. One awkward feature of the levels is that they tend to comprise several distinct screens, and it's not always easy to tell if the level continues off an edge or just ends there other than experimentation.
The graphics are simple, but they're not bad (although a little bit dark), and the sound effects are serviceable. The music is kind of strange -- the little snippets that you get aren't bad, but they only repeat for a short amount of time at the beginning of the level, leaving you in silence for the rest of the time. I don't know if this is a bug or a design decision, but it definitely feels a little weird. The interface is also very spartan -- dying immediately returns you to the level select screen, which can be kind of annoying if all you want to do is immediately retry the level (which is almost always the case).
Overall, Amberial is not a bad game, and you'll enjoy playing it, but it does feel a little sparse and unfinished -- it could use a little bit of sprucing up, and a little more substance, and a little more content. Still, it's an enjoyable way to kill 20 minutes or so.