Thinking about it a little bit, i'm not sure if this counts as the first DTV-specific game - there's a mod of Boulder Dash using 8BPP graphics, but in this case i wrote the game code as well as did the visuals so it's some kind of first! Anyway, it's got a superb tune in by Sean "Odie" Connolly called "Sporting Chance", some 8BPP graphics i'm quite pleased with and plays pretty nicely too (i hope). Here's a screenshot and enjoy!
