Thanks for the kind words, glad you enjoyed it!
Each one of your suggestions was already on my to-do list actually!
I plan on finishing up the Upgrade Info Popup today, I'm going to add a down arrow to the ball on the the bottom of the list so that's a little more clear and I agree on needing to improve the UX for over-writing an upgrade.
These changes should all be in today or tomorrow and you'll be notified when they are.
As far as the board orientation, I do have plans to add additional board layouts in the future as part of a larger update to increase the replayability even more, and a smaller "intro" board would be a part of that.
Thanks again for the thoughts and feedback!