Every little bit helps, and as a thank-you gift for contributing, everyone gets a copy of my line-drawing code (as used in Captain Stretchy-Arms). Works on all of the platforms ExEn supports, plus XNA.
Get yourself recognised as someone who made this possible – have your name immortalized in the ExEn source code.
Early Access: Get access to the live source repository and bug tracker one month before the official release date.
Immediate Access: Get access to the live source repository and bug tracker as soon as this project is funded! An excellent opportunity to help influence the project during development.
I will personally provide email support for ExEn to you for one year. (limit: 6 support incidents – bugs fixed, questions answered, problems solved, etc)
Get the source code* to my Light Blocks game. A great example of how to make a game that runs on iPhone, Silverlight and XNA.
I will personally work with you via email for up to three months to help you port your SpriteBatch-based XNA game to all of the platforms ExEn supports. (valid for 1 year)
I will personally implement a reasonable feature request of yours into the ExEn library for you. Ask me in advance, or hang onto it in case you need something later (valid for 1 year).