Adamant Armor Affection Adventure
The quadruple-A block-style story-based, sneaky-action pandora game Adamant Armor Affection Adventure is now GPLed. Along with it some other games for that platform by the same author (AAA for one [video]) were open sourced.
Sources can be downloaded here (AAAA) and here (other games).
Much more info about the releases along with some internet drama history can be read in this post.
I'm not sure about the assets and their license, there seem to be none included in the tarballs.
/me requesting Linux desktop ports