doors or hatches are what allows samus to move on to the next room. Different colored doors need specific weapons to be opened, here are some of the most seen doors.

Blue doors are the most common doors because these can be with and weapon and is always there

Red doors must first be opened with normal a missile then it turns into a blue door

Green doors must also first be opened, but you must use a super missile and like to red door it turns blue

Metal doors are not like the red and green door instead it blue until you enter it. you must complete a task to open them