Simple Platformer Engine for GameMaker: Studio
Engine including base objects and scripts to easily build a 2D platformer game off of! The code is easy to use, and well commented.
How to use video: http://goo.gl/OuAVei
The example includes a test player, which you can control with the left and right arrow key. He jumps when pressing the spacebar. You can make the gravity negative as well by pressing 'Q'. Collisions are based on rectangular masks = this is not made for precise collision checking, and slope walking is not possible.
To use in your own projects, simply copy over everything in the "YOU NEED" folders. Set all your entities' (this is everything you want to have gravity) parents to par_entity, and set all your solids' (blocks, moving platforms, etc.) parents to par_solid. You can also use the par_solid_expanded for solids with a little bounce - and the moving platforms are all set up and ready to use.
Now, in your different kinds of entities, remember to use the code "event_inherited()" before adding any code to the create or end step event!
You can now edit different aspects of your entities (you can see the different variables in the create event of par_entity) - for example, you can set your speed by adding to the vspd and hspd variables, and you can check if you are currently in the air by calling the inAir variable. You can also change factors like friction and gravity! For your moving platforms you will need to set fix_hspd and fix_vspd to move their fixation points, since they are based off of the extended solids.