itch.io

I tried spamming x and z as fast as I can, but I can't reproduce this bug, does it happen in the middle of the intro, while Undyne is talking? Unless you are talking about the attack animation that Undyne does at the end of the intro? In that case, it's not a bug, it's scripted, as Undyne's first attack will always be with the green soul mode, and you start with the red soul, so when the fight starts she has to turn you green.
Also, yeah, I agree with what you said, though she tries to trick the player with her attacks in the main game too by using spears with different speed and most of all the yellow spears. Though she still fights fair, trying to trick the opponent with a fake attack so that they block in the wrong direction isn't uncommon or unfair.
About the random attacks, I understand why most fangames use a fixed scenario, as you reset the time, so it's like nothing has ever happened and they do the same attacks, though I think that different things could make the battle different, like being in a different position or doing something different from the previous fight would make Undyne consider using another type of attack instead of the one she used previously, so I decided to give her random attacks(which will be much more random and pattern-less in the next update).