One of the first Advance games is unarguably one of the best--even after all these years.
Sure, it's hardly new or even fresh, but it's the difficulty set it apart from others. It had the inventory system an fan instantly recognizes and the castle is still a 2D map you run around and unlock things in. But the bosses! Wow, they get hard. I might even call the game punishing, because at a certain point the game does not let up. This is really the draw, though! Punishing but NOT unfair. Too many gamers now unrealistically remember "great" games from the late 80s and early 90s as being "hardcore" because they were crazy hard, but really they were just put together poorly. (See: nearly any NES game...) Circle is fair, though . Memorize pattern and repeat--no no deviation.
Like I said, nothin new, but just done so well!