There are a few inconsistencies between the appearance of the Omega Metroids in Metroid II: Return of Samus and the one at the end of Metroid Fusion. The first is the size of it, as it was 150% Samus' size in Metroid II, but is now twice her size. This could be linked to the baby Metroid in Super Metroid, who grew larger late into the game. Another inconsistency is the fact that it's only weakness in Metroid Fusion is the Ice Beam, when the Ice Beam had no effect in Metroid II.