When I listened the your earlier version in the discord's devlog channel, the low end felt a bit muddy, but I was listening on my crappy earbuds then so I was going to re-listen again on proper speakers before mentioning it, but totally forgot.. 😅
The way you have the bass sounds playing 2 different lines that low, ends up muddying the low end, so the 2 lines kinda just blend into this mushy texture.
If you took the 2 lines and left the bass one where it is, but raised the other one up an octave, that would help make it feel a lot less muddy.
I'm guessing the old doom games used the same Roland SoundCanvas patch that Nobuo Uematsu used for the ps1 FF games, since that Doom Square Wave soundfont sounds exactly like Uematsu's FF square wave lead sound 😄
If you're ever going to work more on this, adding a new more contrasting section, maybe without the piano for a bit? where the parts/lines change a bit more could be a cool addition.
Good work!