You can use any game engine
Not always the case but in most, any engine is fine
I'll check the end screen and rrestart thing but the Cash showing 0 might be an 8 the font is a little weird. if it has a line through it then it's an 8 but if there isn't then its 0, Sorry about that but I'll see if I can find a better font to use. If you could send pics that would be great!
I think the rrestart is fixed.
It was ok I think it would be nice if there was a tutorial, but the player controller was nice. The animations for the player were way fast and the pixel density was all over the place. Otherwise, it was fun but hard, oh and the death messages were great.
What game engine are you using or is it from just code? (If it's just code what language)