I'd go with a Legend of Zelda themed game myself. With 30 years worth of games for inspiration could make a solid game story.
3 modes for pendants to unlock the master sword and 4-6 modes to get medallions or treasures with a final game mode of battling Ganon for the Tri-force. To get those it doesn't have to linear but all would need to be collected for the final battle.
Side quests like a video mode to dodge the swarming Cocoos, bombchu bowling, shooting range.