The game looks really great!
The Energize tutorial should probably only show when the Energize button becomes available, got confused for a little while here. But that's just a very minor point.
UPD: Fusion interface is a bit confusing too. Especially the "Upgrade to Level X will cost 0" - this gives basically no information. The Upgrade itself seems like it should not really be a thing, just level it up automatically based on the invested currency.
The Fusion tab UI could definitely use some love: at least would be good to have an Auto-Split toggle and a button to invest all resources into a selected nucleus.