ZDoom

I've been trying to run Doom 64 with ZDL, this to play "Brutal Doom 64". I tried to run it with and without the MODs but i always get "GetNumForName: PLAYPAL not found" error. What can i do?

You are likely attempting to load Doom 64 as an IWAD; it does not work this way. Try using Doom 2 as your IWAD instead.

Doom 64 currently can't be played through GZDoom (I've asked about this a lot haha). Brutal Doom 64 is actually a total conversion based on the Doom 2 IWAD. You don't need Doom 64 to play it at all.