Chalk is polished. Looking like something you'd buy for the Nintendo DS, this freeware gem amassed 14,000 downloads in one week. The play style is similar to a scrolling shooter, but even that comparison is kind of a stretch. Control is all done with a mouse, but if you have a PC with a touch screen, that's when this game really shines.
There's not really a story to this game per se, but you control a school girl (teacher?) who's got a magic piece of chalk. You have to defeat enimes by drawing lines with this chalk between them and the bulletts that they shoot. You can also destroy barriers and such in the same manner.
I'm not quite sure how the creator came up with a concept like that, but it's pure genious. Follow the link on the left and try it out.
Why play it? It's an innovative concept and you're an innovative player. It's also fun. You like fun, right?