Thanks to @joaquimp I’ve managed to get a hold of @Noel’s Advanced Platform Engine, a nice tutorial/base engine for making platformers with some advanced features like slopes.
Download it here: http://www.kickbackgames.com/stuff/APE_090.zip
All credit goes to Noel Berry obviously; I didn’t have any part in making this, I just want to make it easy to find once again 'cause it’s awesome.