Pixi has something of the feel of Space Invaders, but with very different and original UI. It is a simple action game in which you control a swarm of pink "pixis," directing them by clicking and dragging on the screen; as you do, arrows appear in the view, representing a vector field, which the pixis follow.
"Boxi" move from the screen top toward the bottom, following somewhat random paths, and attempt to steal your "stars;" if they succeed, you fail the level. As you might expect, additional enemies appear at higher levels, with different capabilities.
It is not a deep game, but charming in its way. Pixi was an IGF Student game nominee for 2012.