Seiklus
Just today I downloaded the Mac version of Game Maker to play with it (yup - I'm on a Mac now, might post about it later). It's been a while since the last game I made in it. Also seems some people are working on ENIGMA - a Game-Maker-to-C++ thing that also features an open source IDE. ENIGMA is pretty interesting actually. It's fun to throw in Game Maker games and see the weird C++ code generated after.
Anyway, then I remembered Jumper/Jumper Two and Seiklus, my favourite Game Maker games. The Jumper series is a classic hard-mode platformer thing like Super Meat Boy, Seiklus is more of a laid back exploration-discovery game. It's really cool and seems to have had some influence on indie platformers. In fact, Matt Thorson (the creator of the Jumper series) was inspired by Seiklus in his ''An Untitled Story.''
A picture from Seiklus:
Seiklus' tunes would be stuck in my head all the time while I was playing it. Here's some:
Time to get Impulse Tracker running on Mac...