YoYo Games has teamed up with Clamber, Jesse Venbrux and Locomalito to bring the following games to Pi:
They Need To Be Fed
Super Crate Box
Maldita Castilla
They can be downloaded from https://www.yoyogames.com/pi
Maybe RetroPie can help the cause of encouraging more Pi game development by requesting distribution permission from YoYo games to include the games for install.
Maybe someone has already installed these on their own setups using an .sh script in Ports.