-The game should no longer try to install XNA 4.0 redistributable on game start. It should instead install naturally through the steam client when you first download the game.
-In game shift-tab steam overlay should work now.
If you downloaded before these changes you should attempt a reinstall.
If you have any issues running the game, attempt to install the XNA 4.0 redistributible manually. If that does not work, contact me or post in the forum and I will assist you.
Coming soon:
Achievements and more steam interaction.