The splitter beam throws three beams, and in games like Metroid, one of the three beams is near Samus legs, so she does not have to switch between diagonal aiming and non-diagonal aiming. As this beam is usually found near the end, it helps to destroy everything easily and get through the different rooms quickly. In doing so, it vaporises any enemy at Samu's feet so that she does not lose momentum, because by the time the player gets this upgrade in Metroid, they have already shown that they can easily take out these enemies, so the game makes it even easier and empowers the player.
This is now in the current demo.
The last point I wanted to give you feedback on is the collisions. Be more permissive, players will not care if a collision is one pixel bigger or smaller. So make the hitbox a little bigger so it's easier to hit enemies, players will not notice that the hitbox is bigger, and that makes the whole experience more satisfying.
This has been adjusted as well and can be found in the new demo update!
It's been a while but I hope you're still following!