@Aethestode, just found a bug on Beta 12's Demo:
You can get the "Myth Book 1" and "Myth Book 4" through Pickup and they seemed to be Key Items.
If you actually try to choose the Myth Book 1, the game restarts out of nowhere.
Wasn't able to try Myth Book 4 because yeah, didn't even thought this could happen.
EDIT: Just got the Myth Book 4 again and the same thing also happens with it.
I recorded a little quick video to show it more correctly:
I really shouldn't saved while Kangaskid had it grabbed.. whatever, I'll just release it, not a big deal.
EDIT2: If possible, please, don't delete the Pickup ability. It's the main reason I actually decided to start grinding levels in the Pokemon Games, you did fixed it when in Beta 10 or so we were able to get Mega Stones through it, so this should be fixable similarly, right? ;_; ..
EDIT3: Myth Book 2 is also obtainable in the same way, and just as the 1st and 4rd, it freezes and instantly resets the game if you try to choose it in your Bag.
EDIT4: Myth Book 5 runs through the same luck, obtainable with Pickup and freezes+restarts the game.
EDIT5: Just found another bug after giving her Gyarados to Misty.
In the Pokemon Center, after interacting with her and before triggering the calling to Professor Oak, if you run away to the CP's 2nd floor and then come back, Misty's position changes and the event feels weird with Misty not being in the position she should be which is in front of the phone. Since I suck at explaining myself, here's another little video showing it:
EDIT6: Also, for some reason, I think that the Running Shoes were disabled at some point inside the Mt. Moon.
I'm trying to use them outside of it but it's no use.
Came back to Route 3 and Pewter but nothing, I still can't use them.
The key itself is working perfectly since I can return from any Menu normally.
EDIT7: I just can't stop reporting glitches or bugs even tho it's a Demo, sorry.
EDIT8: Red just frozen up when I entered in Cerulean's Mart.
The game seemed to be running, but I wasn't able to actually move, nor access the Menu at all, only the emulator internal functions like the turbo or the screen capture were working.
I'm glad that I saved before beating Koga..
EDIT9: Just in case I tried again but it's no use, Red just freezes at the Mart entrance's red carpet.
EDIT10: Just found 2 more bugs:
-You can avoid the Slowpoke Barrier near Cerulean walking through the trees, no cheats used.
-Also, both Dojo Brothers actually teach Mega Punch, when one of them should teach Mega Kick instead.
Also, weird enough, at some point my Running Shoes came back..
EDIT11: I wasn't specting 2 special Butterfrees out of nowhere used by a random trainer, lol.
EDIT12: Horsea's front sprite looks like 3rd Gen's to me, maybe it's just me.
EDIT13: I didn't expected at all Hoenn's Wild Battle Music at the fight against a Voltorb on the S.S.Anne, that was cool <3