This is probably what I would default to (along with OW and R6) as my go to FPS game. It's just designed so well and playing alone or with friends is just really fun. You still have the option to play this version if you download it from the betas, but you can't play online as that has fully migrated over to CS2. But this game will always hold a special place in my heart as it was one of my main gateways into valve, and FPS games as a whole.