It sounds like all you need is a 2D simulator. So i would avoid the overhead and headaches of a 3D simulator. Some notes on your choices:
- Player includes a 2D simulator (Stage) and a 3D physics simulator (Gazeebo) which i think uses ODE
MRDS includes a 3D physics simulator by PhysX
ROS is only an architecture and i don't believe it has its own simulator. although it does have some different visualization tools. it also wraps Player.
Another popular simulator / architecture is WeBots. But i think that is only 3D.
That's all i know. Good luck.
-Ben
