If Equestria Girls gets a video game, I think it's genre will be Point-And-Click Adventure. Like Sam and Max, Broken Age, King's Quest, Day of the Tentacle, and Strong Bad's Cool Game For Attractive People.
At one point, EG Rainbow Dash would be seen playing a video game. Having a hard time deciding what to do next. Thus throwing a jab at the ridiculously difficult puzzles in King's Quest: Rubble Without a Cause.
In case of musical numbers, the rhythm based minigames will be similar to Dance Dance Revolution. Which is just four directional arrows.
For puzzle solving, you can use your inventory, powers, or talk NPC's. For example, you can take advantage of Sonata's (if any of the Dazzlings are in it) to solve a puzzle.
All of EG Fluttershy's puzzles don't involve ticking off people. So they're going to be solved by dialogue, talking to animals, using inventory items on foreground items.
While playing as EG Pinkie Pie, there should be an achievement for using the party cannon on every character she can come across.
Using inventory items/powers on the wrong NPC may occasionally result in a unique reaction. Reactions that are sometime easy to miss. Or the first thing that comes to mind, but is not actually the puzzle solution.
Reactions From Player Characters
Each of the Humane Seven will have unique dialogue about their own inventory items and/or powers. For examples. 1) Sci-Twi pointing out that one of her inventory items doesn't go with a foreground item/NPC. "Those don't go together". 2) EG Applejack being commanded to lift something that doesn't need to be lifted. "I'm not going to pick up that"! 3) Using inventory items on the wrong foreground item/NPC may result in EG Rainbow Dash saying that it won't do anything interesting.
What do you think?