^Assuming you're talking about the game with Kain & Cecil it is truely FFIV. If you are a role player like myself I would switch systems because the DS is an RPG jack pot. DS has an amazing catalog of games of all genres as well. To be honest PSP sucks balls for RPGS. I reccomend you trade it in at your local game store and you'll get about $80 bucks used for it in which case you have 2 options.
Buy the original larger DS for $79.99 used
Or buy the newer DS Lite for $119.99 new
Either way you can't go wrong with this investment, and it won't cost you much, if barely anything at all much if you trade in your psp and games. You will have no regrets