Thanks for playing, this is really useful! You're right about the spacebar, the hint only says "tap".
About the vertical obstacle: in your screenshot, that glowing shape is the finish gate, and the "Level complete!" panel means you had already finished level 1. So I think that's on me, because it clearly didn't read as a finish. Did you notice the Next button, and did it work when you tried it? And before the panel appeared, what did you think that shape was?