In my opinion one of the thing that makes the game so easy is the rune magic.
I guess I'll do the same.. and this is without any extra leveling up. Just going through the story and defeating enemies on the way and getting 108 SoD.
Suikoden: Really easy, the only thing that made it harder was the immunity.
Suikoden II: Can be annoying but given the very powerful runes in S2, it was really easy.
my battle against the final boss)
Sukoden III: Not played, but seen it on youtube. Didn't seem much harder than S2
Suikoden IV: This is the only boss that defeated me on the first try. But with Ted's Soul Eater and the powerful unit of Snowe and Lazlo this boss was a little harder and took a little longer to beat.
Suikoden Tactics: Pretty hard if you didn't watch out. (Not counting that rune cannon 1 on 1)
Suikoden V: Killed it in a few turns on the first try.
Hardest: Suikoden Tactics
Suikoden: Most bosses had a good amount of HP to least long. Bosses didn't move more than once which made it harder since all power was focused on 1 attack. So it could rape your party. Image Luca just attacking once but it's 3 times as strong! Pahn vs. Teo is hard if you don't know exactly the quotes.
Suikoden II: Only the first boss was a little difficult if you didn't level up. The rest didn't least more than 3 turns, except Luca. But IMO he isn't that hard either. Just get as many Fire Emblem's as possible. (http://www.youtube.com/watch?v=SXedbsqAQls
my battles against Luca, without leveling up) Bosses in this game just didn't have enough HP or defence to least long against powerful runes.. But now more bosses could use Runes too which could be deadly. Culgan and Seed were dead in 2 rounds.
Suikoden III: Not played, but some bosses really seemed difficult to me. 3 chimera's, Yuber, Sarah and Luc seemed very hard. If you didn't kill a lot right off the bat I'm sure you're in trouble.
Suikoden IV: The first Suikoden where it was easy to revive fallen characters. But there were barely any bosses in this game! And none gave me a hard time, except Moving Island if you had too many short range characters.
Suikoden Tactics: Bosses were a little more tough but most of them were easily defeated with 3 powerful attacks.
Suikoden V: Bosses barely had any HP, I could even kill some in 1 turn...
Hardest: Don't know lol but I guess Suikoden was a tad bit harder than the rest.
Suikoden: The random battles were so easy, thanks to Kai unite and Hell which eliminated harder enemies. And one enemy with a lot of HP: Deadly Fingertips. Complete dungeons without getting hit.
Suikoden II: The beginning could a little challenging. But after the Syndar Ruins there wasn't much difficulty anymore... Especially that most party's couldn't survive Dancing Flames or The Sheddering.
Sukoden III: I WANT TO PLAY THIS GAME!!!!!
Suikoden IV: I think the random battles could be a tough, as the normal Kooluk guys could cast runes too and had quite some HP. But again the runes raped enemy party's, but not as easily like in S2.
Suikoden Tactics: Yay no random battles
Suikoden V: EASY
Hardest: Suikoden 4
Suikoden: Easy to get used to and you can cast a lot of spells. But can only equip 1 rune.
Suikoden II: Very good combat system, lot's of different runes to choose from. Either put on weapons, more rune magic to equip.
Sukoden III: Cannot play this one...
Suikoden IV: Dumbed down unfortunately...
Suikoden Tactics: You have skills again, you can use 10 characters which is nice. Battles required good thinking. I got quite some game overs.
Suikoden V: New formations.. don't see what was so great about that.
Hardest: Suikoden Tactics
Suikoden I: Dungeons can be easily cleared in 5-10 minutes max.
Suikoden II: Dungeons took a little longer but not that bad. The Syndar, for the maze, and Matilda, for the high enounter rate, were the worst IMO.
Suikoden IV: There were barley any dungeons to begin with howevere the ones it did have were ANNOYING!!!
Suikoden Tactics: None...
Suikoden V: Only the Syndar related dungeons were a pain, I had to use maps to clear them.
Hardest: Suikoden 5
Easy but I use guides to find them.
Suikoden I: Easy except some required some dropped items to find. And keeping Pahn alive can be challenging. Found all on my own. But the last blacksmith and Leon could be tricky to recruit.
Suikoden II: Not that hard either, and found them on my own.
This was before I had internet, so it was quite challending but with a guide none are hard to find or take a long proces to recruit.
Suikoden IV: Also very easy.
Suikoden Tactics: Very easy to find, I think the easiest.
Suikoden V: A lot of characters are missable, some were very short termed. And a lot had extra dungeons and quests to do. AND THE MOST ANNOYING CHARACTER: Where you had to raise and lower the price of salt..... Dang that was so annoying!!!
Hardest: Suikoden 5
Suikoden: Just lucky Rock, Paper Scissors but the ninja's made it easy.
Suikoden II: Battles were also easy since most were just time limits, you didn't have to do much. Also required some luck, but it wasn't so bad. But I liked these battles.
Suikoden III: On youtube these seemed pretty hard to me, but I liked how it also depended on your levels and equipment.
Suikoden IV: OMG these were so easy.
Suikoden Tactics: Didn't have any.
Suikoden V: Nice system, except that it could be very chaotic. Going from land to sea all the time. But IMO the battles were not very hard.
Hardest: While it's hard to decide, I think Suikoden III. Otherwise Suikoden V