By this time, I'd figured out how to
• Randomize a position
• Spawn the obstacle from that random position
• Make the walls move and destroy themselves when done
• Add a HUD and update a points counter
• Destroy the wall and points colliders once hit (no accidental 2nd hits)
I'm having a lot of fun thinking about what else I could do with this, rather than just adding a game over screen and calling it done.
With the purpose being to learn, I think it's good to explore fun ideas to keep the up motivation for learning high. I might experiment with making some sort of proximity based material to show if you're close to the wall or not based on a radius from the player position. Also think it would be cool to add fun events as points build up, losing points if you hit the wall, but you can keep going and keep making progress.
Anyway, I do think I'm learning a lot. Getting slightly more and more comfortable with node names, actor references, common practices, etc.
Wonder what will happen next...