The first "game" on Steam 1.0 was a dedicated server app released immediately before CS1.6. The people with the lowest SteamIDs are server operators. Valve bribed people to use Steam by making all HL1 games available with any HL1 engine game CD key.

My steam id is 10###, was required to play half life multi-player / counter strike.

Steam came out 1 year 2 months before Half Life 2.

They didn't really 'bribe' people, it was more to do with 1.6 CS only working on steam and patching was done via steam.

Registering any of these boxed games on Steam got you access to all of them: HL, Opposing Force, Blue Shift, Counter-Strike, Team Fortress Classic. + some Valve made mods: Quake DM, and Ricochet.

That's a pretty good "carrot" to use Steam if you ask me.

That may have changed after I got steam.

I only had Half Life, and Counter Strike was free when I started playing so I only got HL / CS. I didn't get the others free until HL2 came out...

This is what you should have got with any retail HL CD key:

https://steamdb.info/sub/1/apps/

I can confirm it worked with HL1, CS Retail and Blue Shift keys.

Still waiting for Ricochet VR.

Well, my point was that HL2 was a Steam-exclusive.