Community bug fixing and updates to the original Spelunky for PC
Use Gmk-Splitter to turn the repo back into a .gmk
Something along the lines of:
java -jar gmksplit.jar /spelunky/ spelunky.gmk
java -jar gmksplit.jar /config/ config.gmk
Edit the gmk files with Game Maker 8 (not 8.1!)
Then use:
java -jar gmksplit.jar spelunky.gmk spelunky
java -jar gmksplit.jar config.gmk config
to export your changes back to the repo format.
Changes should always be made in Game Maker 8 for compatibility reasons. Current windows builds for players should be compiled with Game Maker 8.1 however.