Here I have created the mob skin of the Filth Monster with arms for the Ultrakill Jam.

(In the game the monster have no arms, but I like it more with existing arms)
I loved the game Ultrakill very very much and I thought the game has a lot of potential.
Unfortunately, the game is still missing an essential feature, which made me quickly forget the game after I had played through it.
The developer did not include multiplayer.
That you can play this kind of game on a local LAN with friends or Online as WAN is simply essential.
The many secrets didn't improve things either.
The mod version Multikill with Jacket, BepInEx & UMM just doesn't run well enough.
Nevertheless, I had once created this skin to realize an Ultrakill area on a 1.12.2. server.