I can't comment on the technicalities, but I had to post to say that you must play some of the Half-Life mods, as some of them are fantastic.
I'd rcommend:
Azure Sheep (the best HL mod I've played, it's superb, and you get to explore and fight in the parts of Black Mesa (the science complex that the game takes place in) that you only see from the tram ride at the start of Half-Life). In this mod you play as Barney, the guard who you play as in Blue-Shift, but Azure Sheep is massively better than Blue-Shift.
USS Darkstar
The They Hunger Trilogy (you kill zombies (this came out a few years before *every* third first person shooter involved zombies!) and it's really good, with a Lovecraft style story and setting. It starts out slow, but gets better and better as it goes along).
Opposing Force (the first official addon (the second and last addon being the disappointing Blue-Shift), and it's fantastic. It takes place at almost the same time as Half-Life, so you see Gordan Freeman (who you play in Half-Life) several times, as he goes about his business that fateful day). This mod is commercial (all of the others I've named are free, only Opposing Force and Blue-Shift have to be bought) but it's only £4 on Steam (https://steamcommunity.com/app/50 and is well worth it).
Offhand I can't remember the names of more great HL mods, and these are are very old, as I've not kept up with the HL modding scene for years. But if you like Half-Life, then give these mods a try.