Hi there! I have played this game for an hour or so now. Despite there being a lot of bugs, the game is still fairly enjoyable. I have to refresh a lot (press menu and the run button at the same time) I would highly recommend if you play this to save often if you are really trying to play through it. Here are some bugs I encountered:
I had a bug where in one run I did the beldum did not get collected in the beginning so I never got it.
Sometimes, tea magma would walk past you before even talking to you and it was really odd.
A lot of times, my game would glitch out in battle where I am not able to select anything and have to refresh.
It has only happened a few times where I get stuck in the UI of a menu but I can hear myself walking around in the world still.
I had multiple game breaking glitches where the same prompt keeps popping up and redoing itself like one that was really bad, my pokemon were leveling up mid battle and it took me out of the fight, kept saying my pokemon were leveling up, and going black, then going back to the overworld screen for a second, then repeating the cycle.
The joystick often breaks the game, so I just use the d-pad.
The move bounce breaks the game.
Thats all the bugs I can remember but the game is really good for just being a demo. I also find it best for things you are not prompted to press a for, let it play without spamming buttons cause it helps the game freak out less. Will be playing more.