+1 on the resolution issue.
Before seeing this comment, I had no idea there was a blue gate at all. It wasn’t in the visible area when I played it (in web browser on MBP 15”).
Thanks for confirming this, too! Hmm, the gate not being visible plus the text being small definitely implies some resolution shenanigans. Would you be able to share a screenshot of what you see when you load the game? If the top of the embed window is visible onscreen but the gate at the top of the level is not, that is baffling to me and I'm having trouble visualizing it.