Half-minute Hero or 30-second hero, whatever the localized version is called. It's pretty fun and has old pixel graphics.
Also if you haven't played a SMT game, Persona 3 is pretty good. They also have Persona 2 ported and it's okay. If you don't like dating sims then iono about this.
Lumines is a must as a puzzle game. It's like tetris but not and it's pretty addicting.