Yeah, it's always had really strong art direction - still holds up, and you don't notice missing shadows so much in the middle of a frenetic sequence anyway.
Good to see ray tracing coming along. You could get the same shadows and lighting in a modern rasterising engine now as demonstrated in the RTX version, but at the cost of much more development time. Graphics like that being available to smaller studios and larger games being feasible for bigger studios would be great. HL2 is massive compared to modern shooters, and not having to spend forever tweaking each scene helps with that.
Indeed. Here in the UK, people can request that their water company should add it in if their water supply is low-fluoride, for instance from a reservoir, and the water company must add it in.
Back when I used to work in water, that was always the stuff that gave me nightmares. Concentrated hexafluorosilicic acid is what we'd use for dosing. We'd test all the equipment in the chemical room on plain water, drain it out and then literally brick up the doorway. Site would be evacuated during delivery - delivery guy would connect everything up in a space suit, hop in the shower afterwards. Lasted for ages and ages, since you only need the tiniest drip in the water supply to get what you need, but the tiniest drip on your skin would be enough to kill you as well; its lethal dosage is horrifically small.
Made working with all the other halides much less of a concern - we use shed loads of chlorine, but that stuff is much much less nasty in comparison.