I encountered a glitch in which, when I'd run out of energy, the arm kept perpetually going back and forth across the screen without placing any ornaments, and I didn't get the ending cutscene. The tree is a little bit hard to navigate, but I get that there's really nothing you can do about it, since that's the layout that makes the most sense for a tree. Maybe you can extend the game and add more levels with different layouts that are easier/harder (like the cat's on the mantle above the fireplace and knocking down knick-knacks, or on a bookshelf and knocking down books?) That'd be a fun extension of this concept!
I absolutely love this game, it's adorable and very well done! Great job with everything!