If you enjoyed the first film (like I did), then you will definitely love this one.
The actors were impressive, the most noteworthy being Ha Jung-woo (as always). However, do not let that distract for the other performances. Each of the actors brings life to their characters.
Regarding the characters, the guardians have been fully fleshed out, making each one memorable. I found the first film lacking that and while the guardians were each unique, they were rather forgettable. This movie ups the ante.
The comedic scenes were fun, though not exactly "roll on the floor" funny.
The action sequences were well done and the visual effects were pretty impressive.
Overall, if you think that, like all sequels, this one does not live up to the mark established by the first movie, then you have nothing to worry about.
This movie is unique, fun, and an excellent sequel.