Geometry Wars: Retro Evolved (2005)
It might be a stretch to call Geometry Wars an indie game - it was developed by Bizarre Creations, who were owned by Microsoft at the time - but the fact that it was largely the work of one designer, Stephen Cakebread, who originally toiled away on it as an unlockable mini-game for Project Gotham Racing 2, gives it that outsider edge we're looking for.
The revamped Xbox 360 version, Retro Evolved, meanwhile, was one of the games almost singularly responsible for establishing Xbox Live Arcade as one of the principal successes and innovations of that console generation. As critics and new Xbox 360 owners struggled to find gripping experiences among the initial salvo of 360 titles, we found ourselves turning more and more to the likes of Geometry Wars and Hexic HD. Before long, we realised that the fact we were playing them more than traditional AAA games wasn't just a blip - it was part of a new world order. Weekly Xbox Live Arcade releases became a real event, peaking with the likes of Braid and Fez, both of which proved very influential as well.
Xbox Live Arcade doesn't really exist in the same form any more, but it helped change the way we think about small games sold exclusively through digital distribution, and - perhaps fittingly for a twin-stick shooter about blasting weird space microbes in the confines of a galactic petri dish - Geometry Wars: Retro Evolved was the catalyst.
