28 This article gives more handy tips for designing a platformer. There are tips for movement on ladders and veins, jumping, ledges and platforms, the camera, interface, and other ways to make a fun game.
Platform Game Design
28 
17 This article looks at the process of designing levels for a platformer: from the initial idea to the final playable level.
How to design levels for a platformer
42 This article gives handy tips for designing and building a platformer. There are tips for designing the interface, handling jumping and collision boundaries of goodies and baddies, implementing AI, and other ways to make a fun game.