The Hello Mario Engine is an open source Mario engine for GameMaker: Studio that is feature packed, and designed to be easy to expand upon with user friendliness as a priority. The engine is fully documented with thousands of code comments, and includes tons of different powerups, over a hundred different enemies, and much, much more!
Official Website (Download here!)
What's new in 6.2?
Seven New Powerups: Added Acorn, Cloud Flower, Rock Shroom, Pyre Flower, Swooper Suit, Karate Suit, and Super Crown.
All Seven Koopalings: Added Morton, Iggy, Roy, Lemmy, and Ludwig.
Various Bug Fixes and Tweaks
What's new in 6.1?
16:9 Widescreen Default Resolution
New Powerup: Wall Jump Shroom
Various New Features: Bomb Bricks, Propeller Blocks, Blue POW Blocks, New Net Koopa and Piranha Plant Variations, etc.
Various Bug Fixes: This includes all YoYoCompiler related issues, so you can use YYC export options without encountering any problems.
What's new in v6.0?
Code Rewrite: Newer, cleaner, fully commented code.
High Resolution Filtering: Choose between HQ4X, HQ2X, and no filtering.
Better Checkpoints: Supports infinite checkpoints per level.
New Powerups: Propeller and Boomerang Mario.
New Features: Mechakoopas, green bricks, triple wide question mark blocks, and more!
Many Changes to Existing Features: Better world map level blocking, keyhole animation, convex corner support for wall triangles, and more!