I beat the game a while back (like, 2+ weeks ago) but never actually posted any full thoughts about it, I guess because so much of my impression about Samus Returns wasn't so much about this game itself, and more about what I'd like to see them keep, remove, or improve about it for any potential sequels. As someone who's tried and been mostly unable to really get into the Prime games, I've been hoping for some alternative to first-person Metroid at a time when Nintendo didn't seem to really know what to do with it anymore, but this to me showed that they really don't have to fundamentally change the original foundations like they did with Other M in order to make a good third person Metroid. So I guess that's just how I have to frame my thoughts for this game: in terms of how I'd compare it to a theoretical new project.
More new tricks...and fewer old ones.
I can give SR somewhat of a pass for this since it's a remake, and there hasn't really been a 2-D game with Samus' arsenal like this in a long time, but for as much as I enjoyed SR adding in the Aeion abilities, tying them into a new resource as well as providing an interesting new piece of lore, I wound up feeling similarly disappointed in the way that nearly everything else you get all retreads ground that's become quite well-worn at this point. Zelda fell into this same trap for a long time too, where before you ever booted up the newest installment of the series you knew you'd eventually get a bow to shoot eyeball-switches, a boomerang to grab keys or hit distant buttons, bombs to blow up cracked walls, a power glove to lift boulders, and a small smattering of new items that would fit very specific purposes at specific points and offer little other utility. Same deal here, you walk in knowing from the beginning you'll get missiles, super missiles, bombs, varia suit, gravity suit, the same beam upgrades you always get, etc etc. Aeion's a good start, but some different permanent upgrades would go a long way in making a new experience feel a lot fresher.
Stronger mix of tones and zones, especially in presentation.
The backgrounds in Samus Returns are actually pretty well-done despite some folks' gripes, and each "area" in the game provides some new twists, from underground jungles to industrial mines, watery caverns and religious temples...but those themes are somewhat held back by the trappings around them. It's been talked about quite a bit here already, but the biggest things holding the presentation back are the fairly bland brown-stone and nondescript Chozo-built structure that make up the foreground objects that Samus actually moves around on, as well as music whose only real defining moments come when it reuses music from prior games in the series. There's a lot that could be done to shore up both aspects, and one thing that I think stands to be the most effective in making these areas stand out would be a greater degree of tonal shift between major sections. Super Metroid does a great job with this, swapping areas visually and aurally quite often to provide moments of calm, tension, mystery, wonder, suspicion, and so forth all with regular frequency. These tonal shifts don't feel nearly as pronounced in SR, even though the basic groundwork for them is actually there. Tying in to this...
Better enemy variety...even if it's partly a mirage.
It's not like the standard enemies in games like Super or Zero Mission are all that distinct mechanically, for the most part they all generally function as arm cannon fodder with varying degrees of damage-spongeyness. In that regard I think Samus Returns does a decent job, but it needs to go further. I like that different enemies sometimes require different tactics (like some where missiles or beam burst are more effective, some are best to wait and counter while others you can be aggressive with), but visually there needed to be a little more distinction because the most common enemies wear out their welcome really quickly and it contributes to the sameyness of the environments previously mentioned. You weren't generally running into the same enemies in lower Norfair than you do in Crateria in Super even if they don't operate much differently, for example, and it makes those biomes feel more unique and distinct.
I want a future game to keep the free-aim and the melee-counter, but add some more variety to enemy attacks and their aggressiveness to keep the mechanic from feeling too overused. I was kind of shocked that there's no enemy that you can quick kill by, for instance, using the counter on a projectile they fire at you. Generally most enemies react to your presence, which is cool, but they largely react by charging you, which gets old when so many of them do it. Those that don't charge you either retreat while shitting toxic green slime, or annoyingly electrify whole platforms. I wouldn't have minded more enemy types that are still a bit more neutral. Also they could do slightly less damage thanks.
Speaking of enemies...a bit more balance to the boss encounters would be great.
Some of this is just the Metroid 2 structure where you wind up fighting a lot of Gammas because why not, so some of this particular point might take care of itself with any future game without that hunt mechanic to it. My favorite fights in the game are probably the Zeta and Omega fights because they can be challenging on your first attempt or two, but the fights themselves remain comparatively fast-paced, which is something that falls short in a few other cases. The oft-polarizing
for example, contains quite a few clever gimmicks and good weapon uses, but definitely feels like it drags on longer than it has any right to and between the length and it's general difficulty, I think it has a bad habit of fumbling the game's pacing a bit. A few bosses would have benefit from maybe cutting back on an attack that they're mostly invulnerable during and turning the game into a dodge-fest. It's an easy fix to make the fights more brisk without sacrificing the creative uses for some of the stuff in Samus' arsenal that you don't tend to see during 2-D Metroid bosses.
A more "organic" world and how that changes puzzle design.
This is, honestly, the thing I feel most strongly about after coming off of Samus Returns and informs my biggest hope for later games. Metroid's sense of moving around an unknown world, its exploration and atmosphere are typically great, but there are a few moments still that wind up making the experience feel too video gamey for its own good. If and when they do make another Metroid, particularly one taking place on an alien planet, I'd love for them to take more steps to truly make it feel like a planet and not just a big puzzle box filled with specific keyholes. It started to really bug me in Samus Returns how often you'd be poking around parts of the environment only to bomb a piece of wall and have it suddenly turn into a very artificial-looking block with a missile or screw attack logo plastered on it. Like....what sense does that make? I get that they had to find ways for people not to break their crafted puzzles, but...random bomb-sucking air vents posted in bizarre arbitrary locations? I get it for the sake of playing a game, but not for exploring a world. I'd love to see a setting without ubiquitous doors or mysteriously-regenerating blocks that actually construct everything, but a location that looks and plays more naturally, and an arsenal for Samus where everything still has its uses, but done in a way that makes more logical sense. If Power Bombs are so strong, why can that blast not destroy something where a comparatively low-power missile is necessary, just because it's that color?
I know that the Prime games already take some steps toward this with different materials being more susceptible to different things, but it can be taken further to improve that sense of broadening your arsenal to aid exploration without it looking like SR-388 was built out of graph paper. I want to believe they can do better.