Quote from bartendorsparky:
ok, on my nbmb i got up to 83%. though, for some reason, the file select screen shows only 81%, so two things were never i counted. i assume one is the gravity suit, and dunno what the other would be...maybe a powerbomb expansion or something.
If you collect all 4 PB expansions but not the main PB, it only counts as 1% not 4%... so, I think you counted wrong.