Minecraft Classic had a test for the survival game mode available between versions 0.24 and 0.27. While the later Classic versions were creative-only, code for the survival mode still remained in the game internally.
Survival Mode re-enables survival mode on 0.30 using the game's "hidden" implementation. The mod is released as a jar built against obfuscated names for 0.30, so it won't work for other creative versions after 0.27.
To run Survival Mode, you need to install Fabric Loader alongside Classic. I don't think there's any practical installer for it currently, though, so you might need to fiddle with launcher JSON files manually.
Как поиграть с друзьями с модом Survival Mode?
Мод Survival Mode куда интереснее в компании: поднимите сервер Майнкрафт с уже установленным модом, позовите друзей и играйте по своим правилам. Хостинг Майнкрафт для мода Survival Mode будет готов за пару минут - BungeeHost сделает всё за вас.