The feedback is my pleasure! I'm glad if I've been of service. ^_^
I can very much see where you're coming from on the matter of wanting only a single button. While I think that adding another would be one potential solution for the "shooting" issue, finding a way to solve that issue while keeping the "single button" restriction seems like an interesting design constraint. Plus it does feed into the theme of "uncertainty": "I can move or I can shoot, but NOT BOTH! What do I do?!"
I rather like the idea of including more-intelligent AI. It seems to me to fit with both the visual theme and the theme of "uncertainty": To the former, the planet have faces, which suggests that they might have minds; I also love the idea of those happy planets actively coming after the player. To the latter, after all, the more complex the situation, the more uncertain it's likely to be.
All that said, it seems like you have plenty of ideas, so I'll leave you to it!
Happy dev'ing! ^_^
(Oh, and PS: I like the wordplay in the game's name! ^_^)