Engine: XNA 4.0
Last quarter I worked with a group of three other guys to create a pretty sweet PC game called ParaTerra. We created the game with XNA 4 and Visual Studio for windows only (yuck!). We all had no idea what we were doing and we had to cram the game development into 10 weeks, however we are very satisfied with the end product.
Luckily one team member was a pro at Blender, so all of our beautiful art assets are 3D modelled and converted into sprite sheet for our 2D game.
Or you can grab the source anonomously with svn with the command:
svn checkout http://gforge.soe.ucsc.edu/svn/paraterra
You will need Visual studio or something similar along with XNA 4.0 to build this game yourself. Someday I’ll make an executable.