All the levels i played in this Demo, look like they were made without any care to them.. it's just a bunch of stuff from the editor selected and throwed into it and someone called it a Day.
This might come off rude to you now, but did you put any effort into making this?
Okay let's start:
Peach's Castle: There is nothing really going on here except that you can get softlocked when you take the SMB3 Goal because the Player is unable to exit the screen. I've also cheated myself a leaf to see if the Key does anything but no.. it's just for decoration as it doesn't lead to anywhere so why put it in the Demo when it does nothing?
Zentimax Factory: There's just a bunch of stuff thrown together, the level was made without love or any thought into it just random stuff put into it.. the smb1 goomba are set to friendly while the other goombas die upon spawning. Oddly you save Luigi in this, even though you did nothing to save him, all you did was walk by some friendly npcs and that's it. Also again that is Larry Koopa and not Iggy.
Goomba Plains 1-3:
So Goomba Plains 1 is just really short and bad, random goomba stuff is spawning everywhere and shells are being randomly generated that can even bounce you in the water and kill you into the spikes. Yeah that's 1 theres the exit right there.
2 isn't gonna be better, Goombas spawn from the doors and can hurt and even kill you so you gotta jump around the door, the two goomba generator on the pipe is bad as well since it gives little time to go without hurting yourself. At the end Peach just stands there randomly and now you can play her.
3 isn't any different, you start waiting for the platforms to come back to go through a pipe hit a checkpoint 20 seconds after the start and then dodge goombas again and you can enter one of the pipes get some coins get out and that's it.
The Castle level isn't even a Castle.. it has the same Goombas spawning from doors problem again, and yet again that's Larry not Iggy. Nothing more to say here.
Also pls explain how a Player is getting out of the Stress Level again, there is no exit just a 1-UP Farm since every NPC dies by colliding into each other.
And yeah that's it the Demo is done in like 2 Minutes already...
One thing, a player can choose any char he want's to play but is then forced to Play Mario or else they can't advance. So why not disable this? You can do so in the World Map Editor since you clearly made this with 1.3 as all the stuff is registered with an X in PGE.