you can recharge shields using the last powerup called "wtf???". that's a gradius reference. there's a shield powerup in gradius and it's called "?".
actually, i'm kinda sorry for making last two games. i made them as a form of coping through art so they're are just shitposts. the fact that it is somehow playable is a miracle. now i feel better so i'm planning to make an actual competent game, so stay tuned