English Translation
Everything is different now.
Why is an adverb used here instead of a adjective, Why is Wszystko jest inne not correct
Wszystko jest inne is absolutely correct and does mean “everything is different”, where inne is an adjective that refers to wszystko.
Inaczej is an adverb of comparison, just like lepiej (better), taniej (more cheaply), cieplej (more warmly), etc., and it refers to an assumed continuation of the sentence:
Teraz wszystko jest inaczej [niż kiedyś]. / Things are different now [than they used to be].
Teraz wszystko jest inaczej [niż zwykle]. / Now everything is different [than usual].
Teraz wszystko jest inaczej [niż przedtem/wcześniej]. / Now everything is diferent [from what it was before].