hi! No, you can download free sprite from craftpix. I only played with parallex layer a little bit but it got wrong mentioned by XtremeZero.
Yup you are supposed to kill ghost but i was unable to add that thing because of my exams so i started making it when 4hr were left. i will going to add - a health bar, score system, levels, and a good story to it.
Yes i have a record on making difficult games..XD. you can download Brave Knight - @ and Monster Smash made with godot engine on google play. they are also quit difficult.