Solved it by using gzdoom version 4.11.3a. And I've seen that Matt was using this version too. I guess this version is still better to play mods than the latest version of gzdoom. I don't know actually but I have solved 6 more other mods' problems by using this version. I guess this version still holds up. Anyways, good work with this mod. Playing Plutonia feels good with this :)