Half-Life and Half-Life 2 have plenty of really good mods if you are interested in those, Black Mesa started as just a mod as well.
Some of my favourites for HL2:
Some of my favourites for HL1:
There are many more that I haven't mentioned / played myself.
My top four on steam are:
The next season was announced in December of 2023 and it’s changing studio to Wit Studio, so hopefully they do a good job of it. I’ve rewatched it and it’s great for being both relaxing and engaging at the same time, planning to read the light novel at some point.
Re:ZERO or Ascendance of a Bookworm (underrated in my opinion).
Windows 7, 8, 8.1, 10 -> Fedora Workstation -> Fedora Silverblue -> NixOS
Game was fun and had a lot of potential, it’s a shame it didn’t get popular enough.
You can still get the Retroarch Citra core if that works for you.
I don’t use the Flatpak, but for me the rpc doesn’t seem to work for Steam games, it seems to work for everything else that supports it though.
They’re great on certain desktops, like Fedora’s Atomic Desktops, but you usually have to work around Flatpak specific issues. On NixOS there doesn’t seem to be a declarative way to install them.
I like boomer shooters and immersive sims, so I picked up Selaco and Fallen Aces. Both are good so far. Selaco has some maze-like levels that can be a bit annoying, but the gunplay is very fun and the level of polish and detail is very high. Fallen Aces is awesome for the amount of ways it gives you to deal with the goons.