She's a
Spoiler:with time powers that went back in time over and over again to save her girlcrush from a monster.
magical girl
The show frequently has them using their powers outside of witch barriers. Notably when Homura tries to kill Sayaka and during her training montage.
The entire Walpurgis fight also happens outside of any barrier, Walpurgis is explicitly so powerful it doesn't need a barrier.
The amount of firepower Homura lays into Walpurgis with is a lot more than was used against Godzilla in his movie.