Microsoft's Kudo Tsunoda has said that we're unlikely to see existing games patched to work with Project Natal.
The motion control system's energetic front-man told Destructoid that it involved significant alterations that would likely involve a complete re-release for any game that attempted it.
As at previous conventions, Microsoft showed Project Natal during the Tokyo Game Show using real games as well as technical demos, and in this case had mapped controller-free controls to Space Invaders Extreme and Beautiful Katamari.
Eurogamer's Ellie Gibson and Friend-of-Eurogamer Keza MacDonald were on hand to try this and said the Katamari controls were actually really good, although they did tell us this over Skype while dressed as a cucumber and a seashell.
The fact that old games won't work with Natal isn't the worst news in the world - of the demos we sampled and videoed at E3 and gamescom, for example, Burnout Paradise was weaker than the Natal-specific experiments and tools.
However, it does come on the back of Sony announcing a number of reworked games for its PS3 motion controller. Although Resident Evil 5: Director's Cut will be a new release, patches are expected for the likes of LittleBigPlanet, PAIN and Flower.