I had fun with this one! I don't think it is for me -personally- but I can definitely see the appeal. The tutorial could do with a -bit- more spacing, and the mechanic with slotting people into completed rockets I don't think was ever explained.
The feel of the game was very tight, the sounds effects and the visual effects all worked together very well.
I don't particularly like that the build system is based on time rather than movement (it's a bit much to juggle with the other systems) but I can also see that people used to games like puyo-puyo or tetris wouldn't mind. Maybe a zen mode / easier mode where build energy only goes down when moving a block or placing a rocket. Just an idea, but not necessary!