I'm glad you like them!
I **think** the way it works is that you support at a certain level, and as the total dollar amount of all supporters goes up, Shane promises to make bigger sprites. We pay him a certain amount per sprite sheet, and depending on the level we pledge at, we have different rules for how we can use the art. For example:
Right now, he's going to make a few simple sprite sheets per month, 32x32 pixels per sprite, of themed stuff. If you pledge $1 per sheet, you get to download them and use them for noncommercial purposes. For $2 you can use them commercially. For more money, Shane will start making tilesets and animations, but you can only use those commercially if you pledge more ($8 for tilesets, $16 for animations). For his more detailed animations, $200 would be a steal, so even if you end up overpaying for icon sheets, you still get a great deal overall.
