There are almost too many obstacles in Metroid Dread to count, from deadly EMMI robots to breakable blocks. Doors are pretty innocuous – a particular crash bug notwithstanding – but there are still a variety of them to open across Planet ZDR. You’ll need Super Missiles, the Wave Beam, and so much more if you want to reach every chamber in the game.
One particular type of door is marked by three yellow dots. These are Wide Beam Doors, and as you can probably guess, you need the Wide Beam ability to open them. You can find it in Dairon, right after you activate the first generator. Northeast of that is a Missile Door; you have the Missile Launcher by default, so shoot the cover to get through. In the next room is a Chozo Statue holding the Wide Beam power-up.
With this ability, you can now open the “three dot” doors. Aim your Wide Beam, charge up, and release to hit all three dots at once, energizing the door and opening the way. If you see blocks with the same three dots – these are fittingly called Wide Beam Blocks – you can use the same method to shove them aside. Between the doors and blocks, you’ll have a whole list of new avenues to explore once you’ve acquired the Wide Beam.