According to Wikipedia thirteen episodes aired. I didn't catch it when it came out, but I caught it on DisneyXD. It was actually pretty good. The animation was a little rough around the edges, but a lot of cartoons are that way early on. And yeah, the ending was very sudden. Speaking of cliffhangers and Marvel cartoons.....Wolverine and the X-Men. Surprisingly, despite having Wolverine in the title it was actually pretty good. I didn't bother watching it when it came out, but I caught up later and was shocked that Wolverine didn't completely dominate the show. Actual X-Men and their classic villains were involved. Reminded me of the original X-Men animated series. The first season involved stopping an apocalyptic future brought on by Master Mold. Spoiler By the end of the first season it appeared they succeeded, only to get a vision of the Age of Apocalypse. Then it got cancelled. Too bad, it looked awesome.