in the co-op video you couldn't pick up the battery because you didn't have a "thing". I was wondering why since you could've picked up a "thing" later in the play through ?

the battery recharges an uncharged “thing”.. so you need a “thing” to pick it up. like how you cant pick up a heart when you are full. if yu dont have a “thing” or your “thing” is charged, you are full.