Green Meteor Team
Stubbs & Staircase
Pressure Soft-Body Physics - Simulates a water-balloon like shape that can have 3+ faces using an advanced method.
Dynamic Fractures - Making a single object break into smaller objects dynamically.
Advanced Leveling - Shows how to use a mathematical slope function to calculate level requirements.
Zac's Cartographer - Teaches placing and deleting tiles with GML and can be used to populate maps with geographic features.
8 is required to open most of the examples, some come with executables to run them without it.
It is possible to open them with older versions of GM by using a program called Lateral GM