It is ridiculous that they basically gave you a few screen shots and said "MAKE DIS." I am impressed you are as far along as you are, and can't wait til play.
That's how all Arcade conversions used to get done in the early days, which is why every machine's arcade game releases are unique and have their own feel.
It's a bit disappointing to hear that things haven't improved much in over 30 years, especially when porting a recent original homebrew flash game, and with John Lester and CollectorVision running a kickstarter campaign and getting paid money upfront for these games.
It's both a blessing and a curse depending on how you look at it, and it's the same at a lot of the bigger game companies not just the homebrew scene. I worked on a few cartoon network and disney games, and had zero reference other than "watch the show." I ended up making stuff they liked, and one of the things I made ended up going into a show down the road.
This is not uncommon, and might be an opportunity to flex your creative muscle
