honestly to make things abit easier on you maybe make the game first then add the screens as a diffirent thing this way as your playing the game you can add lewd screens along the way
as stated wall cock suck
or help step sis im stuck vents :)
this way the defeat screen is just her shaming you for being boring while the progress thru the game is were the more enjoyable stuff is
on top of this you could add a lobby area where each girl you have fought will hang out letting you have sex with them after you beat them in their arenas