Metroid Fusion (GBA) - Part 14: Trapped Under Ice
If you thought Sector 6 wasn't too bad, then you're probably going to think Sector 5 is even easier. Samus must head to this wintery portion of the B.S.L. so she can upgrade her Missiles. Since her genetic makeup won't allow her to get the Ice Beam due to the side-effects of the Metroid vaccine, her alternative comes in the form of Ice Missiles, which act in the same manner as the Ice Beam where you can freeze enemies and form platforms out of them. For this being an arctic sector, there's not a whole heck of a lot here that shouts out arctic other than a few rooms here and there. Samus's trek through this sector the first time is a pretty short one too, plus she doesn't have to worry about a boss battle here either. Having said that, you'll see the Sector 5 boss floating in the background after you release the Level 3 security hatches near the start, but Samus won't be fighting it until later on in the game.