This game is definitely worth playing, no matter if you are or you aren't a nostalgic fan of the Dreamcast.
Let's start with graphics. Unlike other PSP games, this one is "transferred" from the short-lived legacy, Sega Dreamcast. So yes, that means that the graphics aren't the best. But for it to be an emulation from the Dreamcast, it's really quite good and it won't be much of a disappointment to many.
In my case, gameplay got a little confusing at first. The controls are quite easy but it takes a little while once you get the hang of it. All characters have different techniques and special attacks so it's cool.
Power Stone and Power Stone 2 are included in this game, plus a "collection" section in which you can see the art gallery and mini-games. Awesome, right?
What's really sad about this game is that there is no online play. It would've been a huge plus if it was added. But at least you can play with friends. Another disappointment is the load time. Now, it doesn't take forever but it might take at least a minute to load a game. But if it's to continue on to another level while fighting, it will take at least 20 seconds.
Overall, this game is definitely worth playing and killing your spare time. It does has noticeable flaws but it won't ruin the addiction and wicked fun you will get with Power Stone Collection. This is a must buy for Dreamcast fans who had the blessing to play Power Stone and Power Stone 2 in the legendary console because this will undeniably remind you of good old days. But if you are just curious and loves fighting games, again, buy it cheap and it's highly recommendable. I would definitely recommend this to any fighting, Dreamcast and Capcom fans. ;)