I don't see the theme, you say "you kill the zombies by reviving them" but I didn't get that when playing. The player moved very slowly for me and it felt like the primary gun was a bit useless when you have the secondary gun be so powerful.
Maybe i'll tweak the game a bit after the jam that seems to be a reoccurring thing both the slow movement and the gun balancing issue (obviously i'll leave the submitted version alone and release a tweaked version later on)