Plugging "Tears of the False God", my favorite Quake mod

gunplay, movement, and enemies are all the same, but the level design and visuals make it feel like a whole different game

idk if it's available standalone, but it's in this level pack https://www.moddb.com/mods/arcane-dimensions/downloads/arcane-dimensions-180-with-patch-1 (on the second floor, towards the end of spawn, right side). that level pack is pretty great in general tbh, but ad_tears is a must play