My solutions for 6 and 7 are (rot13):
Gjb dhrraf
Gjb xavtugf obgu tvivat purpx
Then I’m stuck on level 8 nsgre orvat yvzvgrq gb cnjaf naq ebbxf. Pna'g oybpx gur ovfubc'f fgnegvat cbfvgvba orpnhfr bar bs gubfr fdhnerf vf nyernql erq. Oybpxvat gur zvffvat ovfubc'f fgnegvat cbfvgvba qbrfa'g jbex orpnhfr vg pbhyq unir orra pncgherq ol oynpx'f xavtug.