There's been a lot of good ideas from other anons so far, but you know what I'd like to see in an ENA game?
This whole thing, ENA, vaporwave, it's all 90's as fuck. And you want to know what the hotness was back then? VR. "Cyberspace", "Jacking in", I said jacking IN, not OFF you retards
Lawnmower man, VR5, VR troopers, Reality check! (a comic from then), about a thousand other things. Going "inside" the system was a big part of the fiction of the times.
Well, we're part-way there now. We have VR headsets. So why not an ENA VR game?
It could even be a plot-point; You are an actual person, or at least not a native of ENA's world, and have via some mcguffin stumbled onto her world. It could even be that we are using our "primitive" VR systems to get a glimpse of the place. You get to explore this trippy plain not knowing what the hell anything is, just figuring out things by interaction. Solve puzzles, interact with the characters, play minigames, pet hourglass doges, buy TURRON, dance, and just be immersed in this pentium-fueled screensaver come to life.
Of course, my CV1 (fuck oculus in their assholes sideways) shit the bed recently, and I'm an utter poorfag unable to get a new headset right now, but if there was to be an ENA VR game, I'd go rob a bank or some shit to get new hardware.