From Wikipedia:
"Suikoden IV (143 years before Suikoden V and 150 years before Suikoden) → Suikoden V (6 years before Suikoden) → Suikoden (3 years before Suikoden II) → Suikoden II (15 years before Suikoden III) → Suikoden III"
IV is very slow and being limited to a three-member party sucks. It's probably a lot more fun to play slightly sped up with the help of an emulator. 1, 2, 3, and 5 are great RPGs that everyone should play.
IV's problems are:
1. setting the location 150 years before 1 makes the entire thing inconsequential because none of the characters aside from mainstays like Viki and Jeane are relevant. Ted is in it, but he's underdeveloped. One of the things that makes Suikoden speical is how it ties locations and characters into a coherent world. The only reason to set it 150 years before I is to expand the world - it didn't, at least in a good way.
2. Battle has never been a terrible priority in Suikoden, but IV takes the cake. 3 character battles ruins any sense of strategic sense there was. It's an obvious response to III's buddy system criticism - which was novel and interesting in its execution. They were complete cowards in this regard. The result is a very boring combat system compared to even I and II.
3. Random battles in towns.
4. Extremely slow sense of travel via world map due to slow boat.
5. A barren location. There's only 3/4 towns, and only one major city. The idea of having it set in the Island Nations is that you should have a number of islands that stand on their own that are federation or united nations that are islands. This isn't the case. So most of your traveling by boat is empty water. Wind Waker's world is more populous. That says a lot.
5. Underdeveloped characterization, shoddy writing, and editing, poor villain motivation, poor explanation of the true rune. Just bad writing period.
6. Load times.
Good things about Suikoden IV:
1. Music.
2. Mini games.
