Cocos2D and Spritebuilder
Apportable a San Francisco-based start-up later acquired by Google, paid Scott and me to develop the Cocos2D-ObjC game engine.
While at Apportable, we helped port several games (three or four) from iOS to Android using Cocos2D, and their reimplementation of CoreFoundation for Android. Andy helped out with the Chipmunk Physics integration, the SpriteBuilder editor, and various engine features including: Tilemap improvements, performance testing, texture loading, Wwise audio engine integration, scheduling and race conditions fixes, and lots of code documentation. Scott focused on the core renderer, shader enhancements, and engine architecture… and of course, physics integration!
Scott and Andy were both prominent contributors to Cocos2d-objc.
The demo above is Galactic Guardian. Scott put together some nice design notes about it. Victor wrote a bit about the effects and 2D lighting of Galactic Guardian.