Mari is really not suited to games. For me, personally, it's biggest downside is projection only painting which just isn't very acceptable when you're not using gazillions of textures at high resolution.
It's just a bit overkill.
Mari is being used by LucasArts to make Starwars Level 1313.
They've ported their game shaders over to Mari so they have a 100% the same view in Mari that they have in-game. They can also export shader settings back from Mari to the engine. This makes it much more of a full look-development environment than just a texture painting tool.
All of the assets in 1313 are painted and look-developed inside of Mari.
MARI 1.5 released
in CG & Hardware Discussion
Posted
Mari is being used by LucasArts to make Starwars Level 1313.
They've ported their game shaders over to Mari so they have a 100% the same view in Mari that they have in-game. They can also export shader settings back from Mari to the engine. This makes it much more of a full look-development environment than just a texture painting tool.
All of the assets in 1313 are painted and look-developed inside of Mari.