When it comes to the physics support they are working on a new collision detection system, force fields, fluid interaction, fluid buoyancy, inverse kinematics, rag-doll blending with animation, and multi-threaded physics. We also understand that Unigine is looking at possibly using OpenCL for some parts of their engine.
To see the current capabilities of this advanced game engine on Linux, try out the Phoronix Test Suite and run phoronix-test-suite benchmark unigine. In time for Phoronix Test Suite 2.0 (a.k.a. Sandtorg) we will hopefully have a new, more advanced Unigine demo. The Unigine 2009 road-map can be found at Unigine.com.