DO NOT BUY THIS!
Indievania appears to be broken.
Vote for this game to be released on Steam Greenlight, instead.
Run the installer.
It will detect and install any necessary prerequisites (.NET Framework 4.0 Client, XNA 4.0 Redistributable)
Local multiplayer ONLY!
Requires Xbox-compatible controllers for each player
Windows XP or later
Graphics card with Shader Model 2.0 or higher