So I decided I wanted to have some old school games in the phone, just in case I ever needed to waste some time. And what better time waster than the original pokemon games?

So I decided to search for a good game boy emulator. Quite a few are abandoned and the ones that are still being updated, are either infested with ads or cost money. Eventually I found Retroarch, the all in one emulator. Capable of emulating a wide range of machines, and the reason quite a few of those emulators have been abandoned to support it. It seemed like a great piece of software.

If it had worked.

I only tested it with the game boy core. But that was enough. The damn thing is a mess. It crashes constantly, the interface is obtuse, and often disappears and refuses to come back. The first emulator core I tried refused to work at all. Eventually I decided to use the other available cores and at least it stopped crashing. Now after trying to load the game it just showed a blank screen. I still have no idea how I managed to make it work, I just kept fiddling with the phone, until it miraculously started. And finally, once I managed to get it running, I found the control interface to be huge, intrusive, and without any way to manipulate its size or button position, making the game all but playable.

After two hours struggling with it. I decided enough was enough. Got rid of it, and installed GBC Emu.

It's good enough.

I couldn't figure out how to configure RetroArch on PC at all. Never managed to get this "easy all-in-one" emulator to do ANYTHING. Never even bothered on my phone. I use MYBoy on my Android Phone for GBA games. I don't really play any original GB games so I don't know a good emulator on Android for that. But I don't understand the appeal of RetroArch at all either.

I never had major problems with RA, use it under Linux and on Android 4.2.2

if you use a iphone, there's gba4ios-despite what it says, it plays GBA, GBC, and gameboy roms. I dunno what other options you have for android but I would think there's probably a fork of it for that as well.

And how, pray tell, do you change the virtual keypad size and position, so that it doesn't obnoxiously sit on top of the game screen?
That was a major annoyance.

RetroArch requires user to understand how it works. And even more, it's a bit crazy to setup. I don't even know what the hell the programmers thinking when they are writing the code for it.

First, it requires a core to play rom. You can install it by going to online updater -> core updater and then choose which core you wish to download. The choices are many, and that's quite good if you know what you want.

After that, you can load core, and then load content. Content = rom. I wonder why they don't just call it rom. Seriously. Perhaps to accommodate things like Cave Story or PrBoom. And then there you go, the game runs, and you can play.

Now comes the greatest challenge of all. Configuring input key, and screen rotation on Android. I nearly give up hope. Seriously. Its just insane how much trial and error I must get through to get everything right. All I need is a landscape display with PSX virtual button on top for my android phone. What's so hard about it? Why are you making me mad?!? RetroArch!!! I almost curse you :p

Luckily you excels in my old netbook. Simply install, download core, setup controller, and everything works. At least that's one reason not to dump you yet

I use ClassicBoy for that.
Might be limited if you ain't paying for it. No save states or loading states unless it's for SNES games. But you can play NES, SNES, Genesis, PSX, Gameboy and Gameboy Advance...and all at good performance.

I learned to live with it :( it's the one aspect where RA lags way behind the other emu's

Oh, and another thing. I prefer obtaining my emulators separately. An emulator for the NES, an emulator for the SNES, Genesis, SMS, PSX, etc. The only reason for me to go with ClassicBoy is probably free PSX support.

Quite so. My experience pretty much mirrors yours.
I was aware of its multiple cores architecture, so I didn't waste time hitting my head against a wall on that part.
No, the waste of time was from the constant crashes. Seems like neither the Game Boy nor the GBA cores like to run in my Moto G. GBA cores are an even worse offender, at least I managed (with difficulty) to get some old game boy games running, the GBA, not even that (Strangely enough the GBC pokemon games run flawlessly from the get go). Then, on a lark, I decided to try a SNES core. And what a surprise, these didn't crash, but they ran like crap. Chrono Trigger with its pendulum swing is a great indicator of how refined a SNES emulator is in the first 3 seconds. If it stutters, you know that it doesn't cut it. And lo and behold! Every single core I tried did stutter.
What finally broke me is the virtual keypad overlay. I found no way to customize it. But I did find it to be obnoxiously intrusive.

As it stands now, it's a nice little program for laptop/desktop with a controller. But it fails to even be a contestant in Android devices. It certainly is. I however don't have the tolerance for it.
I'm pretty sure it can be customized though, by manually editing the cfg files.
Which honestly I don't know how, nor have the desire to learn. Yeah, I've pretty much done that.
Classic boy looks interesting, but like MyBoy, it locks load states behind a pay wall.
I've ended up going with some abandoned, but working versions of [Insert-Console-Acronym-here].Emu. They might be old, but they work just fine.
I tried using GBCoid and GameBoid, the latter one of which had worked perfectly on my former smartphone. Unfortunately, the move from Android 4 to 5 didn't sit too well with it. Specially the lack of a hardware menu button.

It's not the only one, I miss that button too.

The only reason I have it installed on my android phone is mgba core. That's the only emulator that has light sensor emulation works. That means boktai is only playable on it.

Other reason was psx support. But since it corrupted my save state of suikoden 2 I immediately throw money for epsxe