2D platformers: a game programmer’s guide High-Order Fun has a helpful guide to programming 2D platformers that walks through how to calculate basic movement, slopes, ladders, stairs, one-way ...

Superpowers is a good program for developing or creating 2D & 3D games for Windows, Linux, Android, iOS. Not for novices & needs some getting used to.

To take Copilot 3D for a spin, browse to the Copilot 3D website and sign in with your Microsoft account. To get some inspiration, you can view the existing 3D models generated by other people.