And by hard we mean hardware - It requires a pretty powerful machine to enjoy...
It seems LugaruHD is HW OpenGL only, software OpenGL wouldn't be fast enough to handle it.
Otherwise, it's pretty nice and very fast on a GF7800GT, in 1440x900 with High details.
Ported by Yannick Erb.
Anyway, Lugaru (pronounced Loo-GAH-roo) is the predecessor to Overgrowth. It is a DRM-free, third-person action game available for Mac, Windows, and Linux. The main character, Turner, is an anthropomorphic rebel bunny rabbit with impressive combat skills. In his quest to find those responsible for slaughtering his village, he uncovers a far-reaching conspiracy involving the corrupt leaders of the rabbit republic and the starving wolves from a nearby den. Turner takes it upon himself to fight against their plot and save his fellow rabbits from slavery.