2K Games and Gearbox Software have released a 2D “demake” of Borderlands, which you can play for free. A 16-bit game, The Border Lands is designed with a late 1980s theme. You can try it out at this link. It lets you play as four characters in Borderlands 2.
This is, of course, part of the promotional efforts for Borderlands 2. That game will be available on September 18th in North America and September 21st internationally. It has new characters and a story that picks up after the first game ands.