Just to clarify, different versions of Half Life 1 have different DRM:-

Half Life (original retail disc) = DRM'd. Can be NoCD'd

Half Life (GOTY retail disc) = DRM-Free.

Half Life (Steam) = DRM'd. Works with Goldberg though.

Half Life Source (HL1 in HL2 Source Engine) = DRM-Free.

Black Mesa = Unofficial "reimagining" of HL1 in the Source Engine. Linux version is DRM-Free.

Half Life 2 (inc Ep 1 & 2) = DRM-Free.

Portal 1 = DRM-Free

Portal 2 = DRM'd. Works with Goldberg though.

As for coming to GOG (or any store that isn't Steam), it's highly unlikely for tribal storefront p*ssing contest reasons that have nothing to do with DRM...

You don't have to have a VR set:
https://www.moddb.com/mods/half-life-alyx-novr
Half-Life Alyx NoVR Summer Update 2024

Haven't tried it yet as it's still on my backlog (Black Mesa and the two others comes first), but people seem to enjoy it.

Thanks for the list, AB2012!