Phantasy Star 0 Mini is a Japanese DSi-exclusive bite-sized version of Phantasy Star 0. It cost 200 yen, and allows for up to four players to team up and face its single stage.
You can choose to play as one of three NPC characters from PS0. No matter who you choose, you start at level 1 each time. Unlike PS0 proper, this is not a game in which you make progress and level up; it’s a pure time / score attack challenge.
Mini keeps track of your time and score for each “run.” A run here consists of playing through a single stage and fighting the boss at the end.
If you’re going for score and an easier experience, you’ll want to take your time and fight every enemy you see. You’ll level up and maybe get some helpful equipment. This is the way I played, and my run took me a little over half an hour.
However, if you’re going for a faster time, you’ll want to avoid enemies as much as possible. This means missing out on xp and items, which will make the boss at the end of the stage much more challenging. It could be a really cool experience to attempt with a group of friends (but probably pretty frustrating alone).
That’s really all PS0 Mini is. It gives you a taste of PS0 and some cool potential challenges if you have the motivation, but there is no progress and character building to be had.