I think I can see what you mean about the powerups. Didn't really cross my mind, but I'll take that into account and learn how that's done, as it'll likely be helpful going forward.
To get past the golden walls, you have to use the pose ability listed in the tutorial. The bars probably could have been explained better. If you collect 15 energy (shown by filling the blue meter halfway) you can use your super attack. The gold bar shows progress. When you have gathered 30 halos, you have access to the pose ability, which will destroy the golden wall closest to the arena.
Thanks for the complement!