If you just want 2d, take a look at SFML (opengl based), HGE (directx based), Moai (lua scripted for mobiles and desktop), Ethanon, LÖVE and the other I can't think of right now. I use SFML at work and I used to use HGE (it's a bit out dated now but much faster than SFML and has a cool particle editor).

Ogre really isn't optimised for pure 2d apps, using it for that would be a waste of space and performance. Plus using billboards or other 2d elements isn't as nice as the typical sprite interfaces in 2d engines.