Open source is not the same as source available. I’m not going to do a deep dive on definitions and licensing, but open source generally means that you are allowed to do what you want with it. It also usually implies that if the creator updates it, that updated code will also be shared.
The leaked Cyberpunk 2077 source code is from 2022 at the absolute latest (released 2024 from a hack done in 2022), is not open source licensed for re-use (meaning any use of it by people outside of CDPR is illegal), and they have released numerous patches, updates, and an entire DLC since.
I know that. It’s not entirely true that it’s open-source, since it does not actually have an open-source license, but it’s true to an extent that the source code is technically out there and anyone who doesn’t work for CDPR can (illegally) use it. The comment was only meant as a joke, I wasn’t trying to be real serious about it.
CrossCode is really good, but it isn’t free. I need to look through my Steam library to see which other games might be open source too. This is the only one I’m aware of, really. ProtonDB might have a list of games that are open source. It’s a great resource for checking compatibility if you’re playing on Linux.
Andor’s Trail - RPG where you search for your missing brother. Still under development, but there’s a lot of content. It’s convenient to fill a few spare minutes or waste hours.
Apotris is an excellent famous-block-stacking-game clone for the GBA (and other platforms), it has a version for Portmaster that will run on many if not all Linux handhelds like the RG35XX and similar, but will also run in any GBA emulator.