Hytale is first and foremost a sandbox adventure RPG inspired by Minecraft, but having been made by a team of top Minecraft modders and community members, it's also built with modding in mind. And when mods are involved, things are bound to get very weird, very fast.
One Hytale modder by the name of "tr7zw", who's behind the time-saving Landmark fast-travel mod for the game, has done the inevitable: they've made Doom run inside Hytale, and it's as chunky and charming as you'd imagine.