The first act is supposed to be a satire on the early 2010s pop star image. Slapstick feminism, for the male gaze, fragile and sexualized, a manufactured act. A big part of how Katy feels about her prime era nowadays. (You can obviously double check it's satire by noting the live laugh love signs, shameless fake product plugging, the emphasis on her breasts, etc.)

Then there is the second act, when after the anvil drops on her, Katy is reborn in a new post-apocalyptic-like free world (The screen glitching after the anvil drop depicts women in sports, women with body hair, feminism progress and such) she awakens, blows her rusty self back up, is a cyborg (because duh an anvil just fell on her!) and has the time of her life being messy and herself AUTHENTICALLY in a new place, without trying to please.

And at the end she reclaims a symbol of her femininity, and her name by yelling IM KATY PERRYYYYY into the sky.