There is no level up system, you have to depend on the 'abilities' you can buy in the shop, but you can only use a few at the time. So you can't make the characters stronger after a certain point. For example, I lost to Johness on the first try. XD And then some other things that are supposed to be easy, were really difficult again. The game with Netero is also way too easy, I always used that as a quick way to get some more money if I wanted to buy new abilities. That's too easy, I got an S rank on that on the first try. Impossible, I say! And then in a later location, on Zebil Island, there's one mission where you just have to collect the red butterflies. It's the second mission at the Piske forest location, which is unlocked fairly early in the story, but even after making my characters stronger and finishing the entire story mode, it's still IMPOSSIBLE to clear that mission! Some monsters are just overpowered, you lose half of your HP after being hit by them once, and then fighting so many at the same time. For example there's one in mission mode where you have to fight a whole bunch of the Great Stamp pigs at the same time, and after that a whole lot of other beasts. Maybe it's just because I suck, but I still feel that missions are ridiculously hard, while others are really easy, the balance between the difficulties is kinda off. If it does that while you're moving or about to make a jump, you suddenly start moving in another direction, so it made me fall down all the time.
The camera makes it annoying, because it resets or spins around at random moments. ^^ Most of the story mode consists of solving puzzles in which you have to jump around on platforms a lot, and if you fall down once, you have to start all over again.
I have no idea how PSP games usually are, but I had more 'frustration' than 'fun' while playing it, to be honest. It was actually very frustrating to learn the game at first, maybe it's not that good of a game technically. But maybe they will show up if I make more progress in the mission or tournament modes.? I'm sure I saw Nobunaga and Uvo in the game's trailer, but I haven't encountered them in the story mode, it just ends after Gon's fight with Hisoka, saying that "the story beyond this point will be told another time". ^^ I finished the main story mode a few days ago, but it feels like there's still a lot more to explore after this.
I've been meaning to talk about it but didn't really get to it. Another thing I've been doing for weeks, a little bit at a time, is playing Hunter x Hunter Wonder Adventure for the PSP.