Super Metroid.

It was an amazingly atmospheric game back in the day... And it's gameplay has proven to be timeless.

Still do a play through every year.

Can't beat the original Metroid.  It's an amazing game.  I'm playing through Metroid 2 right now, and it seems pretty good so far too.  I don't really care for the other Metroid games, at least the ones I've tried.

I’m not in the mood to play 1 or super but they’ve always been my favorite. I’m enjoying return of Samus right now so I’ll pick it.

It’s like asking what’s your favorite color.. the answer changes depending on the context. Metroid 1 was my intro so it has that going for it. Super is the best made game of the entire series. Return of samus is the last one made that feels true to the original formula. I didn’t like fusion. I didn’t play samus returns. Zero M is good.

Metroid other M is the best! I love how Samus just doesn’t use her abilities because some dude tells her not to… for reasons…

Super > Zero Mission > Fusion > Samus Returns

I like every game in the entire series but Super Metroid is my favorite. In fact, it's may favorite game ever. I avoid everything about Metroid Dread since the announcement because I want to experience it as blind as possible. I think it will feel pretty similar to Samus Returns and this is a good thing and a bad thing at the same time for me, but well, we'll see how it turns out. Samus Returns relied way too much on the counter mechanic, I hope it will still be there but just as an option rather than a necessity.

"Ummm I'm burning to death but I won't activate my Varia suit because Adam didn't say I could."

OT: Super Metroid wins this one for me. Great atmosphere, super fun abilities (shinespark!), one of the best game to watch speed runs of.

Bonus: I would love for Metroid Dread to be a step above Samus Returns (which I did enjoy)

Fusion.

Bonus: I don’t know, I guess I want it to be good like Fusion was.

1. Super Metroid (I first played this on Wii Virtual console of all things even though my older siblings owned it on SNES)

2. Metroid: Zero Mission (imo vastly superior to Fusion)

(Metroid Prime)

(Metroid Prime 3: Corruption)

3. Metroid: Samus Returns

4. Metroid Fusion (my first Metroid game, I kind of think that's the case for a lot of the other people voting for it over Zero Mission or Super)

(Metroid Prime 2: Echoes)

(Other M)

(Metroid Prime Hunters)

5. Metroid

6. Metroid II: Return of Samus

I am a pretty big Metroid fan. I also have not bought a switch yet, but Metroid Dread will probably do it. I even used to have a youtube channel where I made short gaming clips before it was deleted in 2011. My own personal Dread discussion video on youtube had ~100k views at the time (can't prove unfortunately, but it was actually a primitive video with windows movie maker) and another 10-15k on game trailers (I found years ago by googling my youtube username but I did not actually upload it there and also can't prove because the site doesn't exist anymore?). I actually think I had the most viewed video on the topic at the time and it was just me anticipating Metroid Dread from the Metroid Prime 3 Easter egg (which I guess I was correct in the long term lol - I thought it was coming a lot sooner obviously). I feel pretty much equal about how much I care about 2D vs 3D Metroid overall. I thought Metroid Prime 4 would be the reason I buy a switch because I did not see this coming.

The only Metroid game I haven't played is Federation Force. It just never appealed to me and character models looked goofy graphically compared to Metroid Prime Hunters. I definitely think Super Metroid deserves its "one of the best games of all time" spot. I really hold all of them in high regard except Metroid II. It was the only time I was disappointed in a Metroid game. 

For me the answer is Super Metroid without a doubt.

But I also want to take the time to give Metroid its fair share of respect. It is common these days to call the original game a broken mess that wouldn't be fixed until Super came out. People complain about the lack of map or the similarity of rooms or the absolute lack of hand holding. But as an 11 year old when that game came out, none of those things held me back from mastering the game. The fact that you start with 30 energy points means that you better get farming and you better plan your energy tank pickups carefully. It is a game to learn through mistake after mistake and to get better. It is a game that when you are at school you are constantly recreating in your mind, wondering how to get to certain points, or how to get to certain points quicker. Metroid was not broken when it first released; it was an absolute masterpiece just like Super Mario Bros and The Legend of Zelda. I'm only saying this for the ears of some younger folk here who might believe that Metroid was some failed experiment when it released. The Quality of Life improvements that were delivered with Super certainly make for an easier, less stilted experience, but that's not to say we felt limited when it released. In fact, it was the most expansive universe we had ever seen in videogames and it was a joy (and a terror) to explore.