Funny, I was gonna say they were 2d, because of the lack of proper shadows and lighting. They don't look like they fit in the environment - the characters' lighting is inconsistent with the environment.

The shadows in the environment are baked, and the dynamic shadows under the characters look like fake "dark ovals" to me. Looking at gameplay for this game on youtube, they models definitely look like pre-rendered sprites.

But I'd hazard a guess and say those sprites were originally rendered from 3d models. But who knows.

I agree.