FINALLY had some time to play with the Zero, I actually considered selling this thing since I feel like im getting my needs met with my nVidia Shield, but I decided to give it a try and damn, im actually very happy and impressed so far, so glad I didnt sell it.
I actually havent played hours with it, only game I have played is Donkey Kong Country for SNES, this is actually the one reason that made me get the Zero, something portable where I could play my favorite SNES roms, something that the PSP simply cannot do at a reasonable speed.
So I booted DKC hoping for the worse and it runs amazing so far, played half an hour, just speed running through the levels and the FPS seems to stay at above 60 all the time.
Here is a pic and gif, sorry for the quality, the lightning isnt the best here.
Im very happy with my purchase now, it almost feels like an original Game Boy Advance that plays demanding SNES games almost perfectly.
The controls are weird though, they are too "loose", there is barely any feedback but its not so bad that its detrimental to the experience, at least in platform games.
its for sure the smallest device I own that can play Donkey Kong Country without issues and its hard to say but I think the audio is better than in Android devices like the Shield.
Now here is hoping it runs Super Metroid without issues as well.
Also, big thanks to the developer of PocketSNES, its amazing!