Metroid 2 by far.
Every time I try to play Metroid 1, I can sort of stand the repetitive, samey rooms enough for a bit, then I die once, get my health down to 30 no matter the amount of energy tanks I have and I just go play something else. Maybe replay Zero Mission, in the time I get my stuff back to optimal levels in the NES game and pray that I don't die again, I could be in Chozodia already.
Metroid 2 has issues, but is not the sheer tedium of the first game.