Let's see if I can offer one suggestion for each of these platforms. 😀

• Batman for the NES was the best Batman game until Arkham Asylum came out something around 20 years later. Sunsoft was pretty amazing in that era.
• Earthbound is my favorite JRPG ever. It was pure wish fulfillment for a tween boy, but even though I'm no longer that, it still holds up because it's weird and charming as hell.
• I didn't care much for the N64 — it always looked like a bunch of blobs with blurry textures to me, and the release cadence was abysmal — but I do fondly remember Blast Corps. It was great fun, and I never hear anyone talk about it.
• OK, four in, and I've already failed. 😅 I never owned a Master System.
• I'm not sure if Panic for Sega CD was actually any good, but it was cute and silly and that was enough for me. The correct recommendation here is probably Sonic CD, but that's a boring recommendation.
• Uh oh. I never owned a 32X either. 😞
• I hardly remember anything on the Saturn. Someone has already recommended Nights, so maybe give Christmas Nights a shot. Games with a Christmas theme are relatively rare. 🤷‍♂️
• I can't recommend my favorite Dreamcast game Samba de Amigo because you won't be able to play it properly without the maraca peripherals, but the Dreamcast lineup was absolutely loaded so it's not a problem. I feel like Shenmue embodies the promise of the Dreamcast: unbridled ambition but without the pieces necessary to quite meet that ambition. It might be rough today, but it's one of very few games where you'll be able to spend hours driving a forklift around. That's gotta count for something. 😅
• I'm pretty sure Windjammers is the best Neo-Geo game.
• We're spoiled for choice again on PS1. I have to go with Castlevania: Symphony of the Night. It's a classic that holds up better than just about anything else on the console.
• I always thought most of the Game Boy's library was garbage. Qix was neat, albeit simple. Oh, wait. You like JRPGs, right? You should try Pokemon!
• I'll go with the 800 pound Gorilla for my GBC pick: Link's Awakening
• GBA was another one of those killer platforms with tons of great games… but the best one is WarioWare.
• DS just had a near endless library of hits. Rhythm Heaven is one of my favorites. Bonus JRPG pick: Bowser's Inside Story
• The only PSP game I played much of was Lumines, but it is actually really good.
• When I was a kid, arcade games were incredible because the tech was years ahead of what I had at home. Now, I see how predatory they were and have trouble feeling good about many of them. Here are a few I like that fly under the radar sometimes. Tapper is a really good game that's fun for 5-10 minutes. Cadillacs and Dinosaurs is one of those 90s beat-em-ups, but with an interesting theme. If you like those, you might also like the D&D beat-em-ups. They have some really light RPG mechanics. Shadow over Mystara and Tower of Doom. Was there another one? I'm not sure. Then, I know there's near zero chance you haven't played NBA Jam, but it's just my all-time favorite.

Hope that helps!

Alright, I'm gonna fire off a bunch of games for a variety of systems:

NES

• Mother 1,l: the version on the gba is preferable as it has less censorship than the semi official translation and has some QOL fixes like being able to run and an easy mode inclusion. The latter I didn't use on my playthrough and enjoyed it but it can be rough and I would not blame you for using it especially if you are unused to jrpgs. Overall mu favorite on the console.
• Megami Tensei 1 and Megami Tensei 2: I group these together as they were bundled in the snes remake which generally a better experience but the originals have some charm. They are very hard old school dungeon crawling rpgs. The stand out mechanic is the ability to recruit demons to your party in a similar way to pokemon or Dragon Quest V but with a fusion mechanic to level them. If you chose to play these over the remake use save states as you will have to use a password system otherwise. Additionally get some graph paper to map stuff out.
• Mario 3: Arguably one of the most polished games on the platform. Basically an improvement over its predecessors in every way.
• Castlevania: Pretty hard action platformer with a Gothic monster movie atmosphere. Lacking the distinct style of later entries but still solid fun.
• 1943: WW2 shoot em up. Simple but has good controls and decent music. Castlevania 3: bigger, badder cousin of Castlevania 1. Features a cast of different playable characters with distinct abilities. Very difficult even by the standards of the already difficult Castlevania 1. -The Legend of Zelda: I doubt I need to say much about this one but I can't stress how ambitious this game is by comparison to many other NES Era games. While simple and a bit jank by modern standards it is very much a whole ass adventure for you to overcome.

SNES

• Earthbound/Mother 2: I'm gonna be controversial here and say the official translation for Earthbound doesn't do it for me. Censorship of things judged "not kid friendly" and the addition of random humor ruined the slightly dark, and slightly more grounded tone I enjoyed in Mother 1. With this in mind I will recommend you play Mother 2: Perfect Edition which is a romhack that reworks the translation and overall greatly improves the tone IMO.
• The Legend of Mana: Utterly classic action rpg with one of the best soundtracks on the platform. Seriously, go listen to the legend of mana soundtrack rn, I'll be here when you get back.
• Shin Megami Tensei: Spin off to Megami Tensei on the Famicom. Much easier post apocalyptic jrpg. Demon recruitment and negotiation is greatly improved, demon fusion is expanded and the roster of demons is much bigger. Nothing quite compares to firing a rail gun at the Archangel Michael. While I'm here I will also recommend SMT 2, SMT if, and Kyuuyaku Megami Tensei which is a remake of Megami Tensei. All are good, some are quite hard though.
• Front Mission: Gun Hazard: Mech game set in the near future where there is endless small proxey wars fueling the economies of large coalitions of wealthy nations. I love escapist fiction... Darkly relevant themes aside this is a fun side scrolling mech shooter with a cool aesthetic and a bumping soundtrack.
• Demon Crest: Somewhat unknown action platformer that has started to get some recognition in recent years because it's just damn good fun. G.O.D.: little known snes rpg that never left Japan. Fan translated it is like a much darker and more adult Earthbound. Has some interesting mechanics.
• Final Fantasy V: Now you might be wondering why I picked this over VI since it's the one that's everyone's darling. Final Fantasy V has the job system where you can change anyone's class on the fly and mix and match perks from different classes. It's excellent fun.
• Chrono Trigger: one of the best rpgs of all time. Just a really well made, well produced, well balanced rpgs out there. There's a reason it's on so many best game of all time lists.

N64 Imma be real with u fam. I don't care for the N64. Don't get me wrong it had some great titles, but most have aged like room temperature chicken. Mario 64, banjo Kazooie and the Zelda games are probably the best aged

Playstation 1

• Grandia: Super charming and cozy rpg. Good music and an interesting battle system.
• Wipeout 2049: the sequel to the anti grav racer Wipeout. Think F-Zero meets the trainspotting soundtrack.
• Front Mission 3: Tactical Mech game where you have a high degree of Mech customization. Also features a cool fake internet with side content and a great soundtrack.
• Ridge Racer 4: Arcade Racer with an amazing soundtrack and great controls.
• Tales of Phantasia: First game in the tales series. Technically debuted on the SNES but that one has some crunchy audio unlike the gloriously uncompressed CD audio of the Playstation. Has a strong character driven story and some surprisingly dark moments.
• Xenogears: Epic multi disc RPG with a unique setting. Imagine feudal fiefdoms with archeologically uncovered Mech suits.
• Castlevania Symphony of the Night: Now there are a couple options. If you want a mor3 serious version with some more features and more challenging difficulty you want the fan translation of the Japanese version. If you want some classic 90's hammy voice acting then you gotta go with the North American release. Honestly the English VA is so iconic I almost prefer it.
• Resident Evil 1-3: Classic survival horror at its arcadey finest.
• Silent Hill: Resident Evil's more serious, scarier brother.
• Koudelka: Gothic horror rpg with full voice acting that is actually quite good if theatrical. Good music too.
• King's field 1-3 and Shadow Tower: First person dungeon crawling from the makers of dark souls. Get ready to get trolled by the developers pretty often.
• Ace combat 1-3: Arcade air combat at its finest. Solid soundtracks and plenty of replay value. Electrosphere is basically the blueprint for the modern ace combat game.

These are my personal favorites. Note that many of these I enjoyed as a kid so I can't 100% be certain adults will like all of them lol. Some of these are also pretty popular so you may have heard of them already.

• NES: Lone Ranger, Super Mario Bros 2, Spy vs Spy
• SNES: Earthbound, Pilotwings, Blackthorne, Super Mario World 2: Yoshi's Island, Kirby Superstar
• N64: Super Smash Bros, Star Fox 64, Paper Mario
• SMS: Didn't play this one much.
• Sega CD: Lunar: Silver Star
• Sega 32X: Knuckles' Chaotix, but I'm fairly certain it would not be great as an adult.
• Sega Saturn: Didn't play this one much either. I remember thinking Nights into Dreams looked really pretty but it felt pretty unrefined, and didn't get into it.
• Sega Dreamcast: Only every played Crazy Taxi on this one.
• Neo-Geo: Never played it.
• PS1: I liked a game called Dragonseeds. FF7 and FF9, and FFT too. Harvest Moon: BTN.
• Game Boy / Game Boy Color: Zelda Link's Awakening (DX), Pokemon Games, TMNT: Fall of Foot Clan
• GBA: Final Fantasy Tactics Advance, Moto Racer, Mario Kart Super Circuit
• DS: Final Fantasy Tactics A2, Mario Kart DS, Professor Layton Series, Phoenix Wright Series
• PSP: I didn't ever have one, or emulate one. But if the Sid Meier's Pirates port is any good, it may be worth a shot!

If possible, update us on how the Retroid Flip is!