Mars the manga

Well, I just finished the Mars series and I must say, it was a damn good read. I'm too lazy to go in depth about it, and I'm not gonna post spoilers or anything. My only complaint is the ending. Idk, it doesn't leave me with the happy, yet bittersweet sense of completion that I always get when I finish a good book or series. I read the ending and was just like, "......hm. So it's over. Good stuff." Not necessarily anti-climactic, but definitely lacking something. For any of you guys who have read it, did you feel the same?