It's done, baby.
https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=1185532802

It's actually very identical to the HUD when you enter Hypermode in Metroid Prime 3.
https://i0.wp.com/www.mobygames.com/images/shots/l/261237-metroid-prime-3-corruption-wii-screenshot-phazon-can-help.png

True, while not Metroid, the Halo HUD on here is pretty identical with some differences here and there.

Metroid Prime HUD -
https://vignette1.wikia.nocookie.net/metroid/images/2/25/Metroid_Prime_Yellow_Exo.jpg/revision/latest?cb=20130112223459

L4D2 Halo HUD - https://steamuserimages-a.akamaihd.net/ugc/615045711043464573/1CA22A0B3F8BF0074E3B67494A61768F61152837/?interpolation=lanczos-none&output-format=jpeg&output-quality=95&fit=inside|637:358&composite-to%3D%2A%2C%2A%7C637%3A358&background-color=black

The Delux Halo Hud is pretty damn close. It even has the healthbar in the right spot.

Well, of course! Seeing something as awesome as this calls for it! Also, now that I think about it... no one has made a Metroid Prime HUD yet. Well, at the very least, I haven't seen one* on the workshop.

Yeah, I gotta agree with you on the armcannon thing. This is something I've wanted for years, so it's nice to finally have it; and make it myself, no less!
Again, it's kinda hard to explain, but I think it's built the same as the level geometry, except there's some scripted rotating and stuff. In the boss of the first one, you have to shoot him in the head, and then the custom enemy in the first one (and maybe the only one, i haven't gotten too far in the second one), you have to shove a bunch. Like, everyone has to shove the enemy. I actually have to get the bots next to the enemy, and they automatically shove him; it probably takes like, 15 or so shoves, but I might be wrong.
If you ever play the map, make sure you have admin system on; the bots will sometimes not take stuff, or even just get stuck.
Also, I see that you've favourited this screenshot ;)

Oh, it's one* of those "bosses" eh? Got ya.. I think?

I wasn't paying much attention to the map, the Arm Canon took all of my focus.. it's just something seeing Samus's Arm Cannon replace a weapon. xD

I might shift my focus more towards mapping; I've been playing a port of a Zelda 1 based map (which is actually where this screenshot was took!), and, as frustrating as it is with bots, and even with how much damn health the first boss has, it's pretty fun. I might try to make a Metroid map, even with custom "bosses" like the guy who made the Zelda map did. Maybe even some custom "enemies", also like how the Zelda map did. The reason I say it in quotations is because it's more of a built thing, I guess. You'd have to play the map yourself to really figure out what I mean.

ah, got it.

Splinks directed me to the discord. Also, I realzied I put server instead of discord, so I've fixed that.