I'm not going to write much about each game, just gonna make a few points.
5) Summoner 2
A Western made action RPG, that very few people played and as such has unfortunately not received a third game.
Basically you played as a a warrior Queen who can summon creatures (well really you transform them) and lead her and her party to save her land. The story is actually a lot more complicated, hence why I'm not going into it, but it's also really well told and worth playing through.
It's an underappreciated gem.
There was also a gamecube port. It was bad. don't play that.
4) Persona 4
I don't really like JRPGS. I'm going to say that up front. I don't like how linear they are, how few sidequests there are, how generic their stories are. I like the few that stand out, but for every stand out one there is another generic Final Fantasy game.
So the fact that my 4th favourite PS2 game is a JRPG should say enough about how great this game is. But of course, I'll give a brief explanation too.
Persona 4 is an RPG which blends dating-sim like character interactions and party building with tried and true turn-based RPG combat that pays a lot of homage to Pokemon(with some nice additions.)
You gather your Persona and use them to give you extra powers in battles, but also you S Link with people to increase the powers of your fused Persona and the effectiveness of your allies in combat.
Also the story is **** great. Simple as that. I have a couple of issues with it (namely that you can tell who the villain is via a gameplay thing rather than the story) but overall it's awesome.
3) Devil May Cry 3
I swear, this is the last number that will be the same for the game and the position in my list.
Devil May Cry 3 is by far the definitive Devil May Cry game. It does everything better than every other game. Well, except graphics compared to 4 obviously.
It had the best, and deepest, combo system. It had the cool "****" system with leveling up unlocking new moves, it had the best story, it had the best boss fights, it was hard.
It was just the best.
And best of all? it didn't even NEED to be as good as it was. Coming off the heels of the steaming pile of poop that was Devil May Cry 2, fans would have taken just a good game, nevermind a mind blowingly great one.
Unfortunately of course they then made Devil May Cry 4. Which was okay, but not great since it was really short and you had to repeat the whole game twice, and all the boss fights (at least) three times.
But yeah, Devil May Cry 3 was great.
2) Shadow Of The Colossus
I actually didn't play this one until quite a while after it came out, but it's a doozy. Imagine the best boss fights you've ever played before.
Now imagine if they were even bigger and even better.
That's Shadow of the Collossus.
Taking amazing boss fights and then combining the actual bosses themselves with some crazy amazing platforming, the game is just outstandingly fun to play. It also has fantastic music, graphics and a really nice and subtly told story on top of all that.
It's not ALL good though. On PS2 the framerate chugs at around 15-20FPS at all times, which is baaad. They are making a PS3 port that is apparently going to be locked at 60FPS though. WHICH WOULD BLOW MY MIND.
1) Metal Gear Solid 3: Subsistence
So, I'm a sucker for the Metal Gear franchise. I've played all the games, the original MSX games (both included in Subsistence in fact), all the spin offs, the portable games, the main series, everything.
I've done it all.
And I've loved it all (except MGS4, that game was **** terrible, but that's for another day.)
But the best of the lot, and by extension the best PS2 game in my person opinion? You guessed it, Metal Gear Solid 3's limited rerelease: Subsistence.
Adding a new camera to Snake eater (Snake Eaters was kinda bad because the levels were huuuge), Subsistence improved an already near perfect game. The perfect combination of stealth and action. The perfect blend of different types of environments, a fantastic story, outstanding boss fights that are the best in the series, and actual emotional tie to The Boss, technically the main villain?
Yeah. It's a damn good game. One I've played many a time and will play many more times over the years. Highly recommended.
It's also getting a PS3 (and 360) rerelease later this year. So look for that if you haven't played it.
(There's also a 3DS Port, if you're into that. But since it'll no doubt have worse controls...)