The humour were reduced greatly, in addition it has a solid story and plot.
The game itself were enjoying to play with a different love story for each of the Angel Troupe. The difficulity is moderate to each person, to me it was very easy.
The game itself already ended in 3 series:
1. Galaxy Angel
2. Galaxy Angel ~Moonlit Lover's~ ( this where chitose joined )
3. Galaxy Angel ~ Eternal Lover's~ ( The closing for the 3 game )
Why i said the game ended i suggest you play it yourself and you will understand ( I don't want to be a spoiler )

The Manga is still continuing in Japan, the first session were already ended and now they serialized the 2nd session under the name Galaxy Angel 2nd.