The best falling block concept since Tetris. The ability to attack your opponent with your performance added such a level of chaos to this genre that would be replicated by numerous other games in future years. It forces you to play faster to outdo your opponent and in turn it basically makes the entire concept more challenging because the better your opponent is, the more it forces you to play even faster to outperform them. I like the art style, and the silly voice acting, but I love the gameplay, it's just pure catnip to me.

visuals are very charming and cute-looking, and it is very exciting to play to this day.. until puyos falling speed becomes uncontrollable and you find yourself unable to rotate puyos once they're in-between the columns. it is rather sad you cannot toggle it. maybe on keyboard it would be easier to control, but on gamepad i've had a hard time with this annoyance.
as for the music, satan's banger of a theme really helped me to keep my sanity while trying to beat his stage.
of course there's some major issues that have been fixed in later games, but this one started the formula and established it instantly and greatly, so i think it totally deserved a 3.5 :D