8BP is free and opensource, available at https://github.com/jjaranda13/8BP, including sources , demos, manual and games
There is a blog (in spanish) by 8BP author (Jose Javier Garcia Aranda) at http://8bitsdepoder.blogspot.com.es/
Manual is in spanish....but i will start to translate it to english! if you want to help me, you are welcome
'''Main features:'''
- multi-directional scroll
- allows in-game music during games based on WYZtracker tool.
- layout ( which is a kind of "tile map"), with colision detection.
- commands for move N sprites at the same time.
- routing sprites through user-defined routes, simplifying game logic
- complete sprite editor included (SPEDIT).