Nintendo has offered to fix the save files of anyone trapped by a door in Metroid: Other M that snaps down and prevents further progress in the game.
The pesky door in question is located after a boss fight in Sector 3 and according to Nintendo the problem only occurs if you do not proceed through it as soon as you pick up the Ice Beam. Go back and it may snap shut forever.
"If this issue does affect your game and the door is locked preventing you from further progressing in the game then please contact Nintendo Customer Support who will provide you with details on how we will fix your save file free of charge," the platform holder explained.
Hopefully you're not affected, because then you'll surely enjoy the rather lovely Metroid: Other M, which picked up 8/10 in its Eurogamer review last month.