Mi

Mi is an excellent, minimalist puzzler with wholly original gameplay. Each level, you right-click to launch your soap bubble; elsewhere on the level is an exit. (In some, multiple soap bubbles launch simultaneously, and must be guided to different exits.) Rotating gears must be avoided; they pop you like the soap bubble you are.

Your only control is "left click to divide". When you do, your soap bubble splits in two. Their paths diverge, obviously; if you were heading in the X direction, each of the two bubbles now have the same X vector component, but one has a vector component in the +Y direction, and the other in the -Y direction.

You can only split when you have a single bubble; but if one gets popped, the survivor can re-split.

Walls cause you to reflect (angle of incidence equals angle of reflection). Success in a level means careful timing of your splits, to avoid gears -- and in some cases, using the change in velocity imparted by a split to maneuver.

The game is apparently in alpha, but it is already quite polished, and already demonstrates that this one-button control scheme can accomodate a wide variety of level designs and challenges. Unless you have no patience at all for skill-and-action gameplay, Mi is well worth your time.

There's a gameplay video at the developer's site, but I won't embed it here, as it contains some spoilers.