mednaffe VS higan

I use Mednafen with Mednaffe front-end (for GB/GBC, GBA, GG, SMS, Genesis, NES, SNES, Neo Geo Pocket Color, PC Engine/Supergrafx), plus Duckstation for PS1, Rosalie's Mupen GUI for N64, MelonDS for NDS, Redream for Dreamcast, and MAME standalone.

Mednafen is the best Turbografx emulator. It has no GUI built in though so grab this too if you need it. Either that or just use RetroArch with the Mednafen core.

I would suggest you also trying Mednafen (https://mednafen.github.io/releases/) & mednaffe frontend (https://github.com/AmatCoder/mednaffe/releases). Beetle PSX core is based on Mednafen. While Mednafen lacks some enhancements (e.g. GPU acceleration, upscaling of internal resolution, or fixes for PS1's wobbly geometry and texture warping problem), its software-based renderer is also more light-weight than Beetle PSX and has much better compatibility than ePSXe. If your CPU isn't too weak, it should run smoothly.

Mednafen with a frontend like Mednaffe are a great option for the NES, SNES, and a bunch of other 80s & early-90s systems (Genesis, Playstation 1, Saturn, etc.).

For a Mednafen GUI, try Mednaffe and MedGUI Reborn.

Mednaffe, an incredibly handy front-end that streamlines the process for you + I. In that link above, Github's layout may look intimidating, but just download mednaffe.0.9.2-win.zip. I'll go more into Mednaffe once we actually get what we're looking for.

Analogue SuperNT if you want close to actual hardware, cart support, controller support on an hdmi platform. But if you just want to play the games, a good emulator will do wonders. Higan will do most old systems flawlessly.

Self taught developer in what systems with what languages? If you want to learn these concepts implement them in your language of choice. You would likely learn the most using C to do so. A great starting point are the various flavors of coroutine. There are a few great implementations on github, in various projects. It's good to read those while learning so that you understand WHY the various types of coroutines exist. Why does the Higan emulation project use cooperative coroutines on a single thread? https://github.com/higan-emu/higan/tree/master/libco You can study both the implementation of some idea and its use by finding projects like this on github and reading the source.

mGBA runs on everything and has tons of features, but isn't 100% accurate. If you have a decent PC and want the best possible experience, try Higan instead: https://github.com/higan-emu/higan

Don't forget the emulator Higan (formerly bsnes) for your older needs (Famicom / NES, Famicom Disk System, Super Famicom / SNES, Super Game Boy, Game Boy, Game Boy Color, Game Boy Advance, Game Boy Player, SG-1000, SC-3000, Master System, Game Gear, Mega Drive / Genesis, Mega CD, PC Engine, SuperGrafx, MSX, MSX2, ColecoVision, Neo Geo Pocket, Neo Geo Pocket Color, WonderSwan, WonderSwan Color, SwanCrystal, Pocket Challenge V2)

Snes9X is generally considered the best general emulator, if you happen to try to run one of the 20 or so games that Snes9X has issues with, Higan is there to save you as it's cycle accurate on SNES games, however, be warned that Higan is quite resource intensive because accuracy isn't cheap, so only do so if you really want to play that, as even Higan's original dev recommended to use Snes9X over Higan for most emulation

Download Hub -- https://github.com/higan-emu/higan/releases

In the second scheme, you build some abstract interface to system GUI libraries, whereby they can be polled for input and asked to lay out widgets. Then you implement the interface in terms of every host that you want to support. This is essentially how higan&co work (see specifically hiro).