I know bevy and I know that it is certainly far behind Godot. It’s written in Rust though, so that gives it a lot of future potential, compared to Godot especially.
I think this is a really nice idea! By having different planets, this is basically four different expansions in one, plus the space stuff. I am really interested in what will make the planets special. One looks kinda deserty (no water?), one looks very green (dangerous fauna?), and the last one rather icy (will the cold be a problem?). Whatever they chose for the planets, I am sure it is gonna be really interesting!