The Half Life GOTYE can probably be installed and played no problem. The CD key is probably already bound to a Steam account, otherwise that’d be another way to play it and easily have all the updates.

Starcraft/Brood War and Warcraft are all still playable as far as I’m aware. ActiBlizz hadn’t killed off old school Battlenet last I’d checked. Private servers are also still a thing for classic blizzard games. Same goes for C&C. Private servers a’plenty. PVPGN was still the thing for Blizz games (up to a certain patch because they changed some server side stuff) and Westwood Online games. There’s also a separate project specifically for Red Alert games whose name escapes me. Also the OpenRA project.

The last flight sim I played was Red Baron II/3D, back in the Sierra Online and MPlayer days (pre GameSpy Arcade), but I’m familiar with IL2. Been a few years since I checked in on it but it had a fairly active player base and modding community. VFWs (Virtual Fighter Wings) were a thing in that and in Microprose’s Falcon 4.0 where some players took it very seriously and were quite skilled at formation flying and such. I still have my copy of Falcon 4.0, 3 ring binder manual, map and all. Wasn’t good at it but I was always amazed at how technical it was.

Baldur’s Gate 2 should still run. Same for the original and Icewind Dale, if they’re hiding in the box somewhere. I installed those from CD a while back and they worked fine.

I should probably try in my Deck next. Dollars to donuts I bet they’d work - I’ve installed other games on it from CD just for shiggles. Truth be told, Linux is probably preferable for a lot of older games since a lot of work has gone into wine/proton explicitly for compatibility. A lot of really old Windows games, that are unplayable on Windows today, run amazing on Linux.