But it doesn't need to be.
I agree, which is why I said, "but it'll be fun." You are speaking with a guy that loves cheesy 80's action flicks, after all. I would totally go watch "Blasto: The Hanar Spectre!"
Ever left a chapter on a serious cliffhanger, and then taken forever to get the sequel up? I'm worried I may end up having done that with BtLatD's latest chapter. It's a complicated thing.
As for cliffhangers left unresolved...I've only done it once. There was a story I wrote for FF8, wherein I was getting into the final phase of the story, and some of the main characters were captured and being tortured for information. Then I dropped the story.
By that point, the story had gotten away from me, as I hadn't really developed proper self-editing techniques. The project was little more than an excuse to sandwich in scenes I had an inkling to write. I didn't realize why I never bothered to finish it until years later, when I realized that the plot was a mess, and nowhere near as cohesive as it needed to be.
I still had a great bit of fun writing it. If I ever pick it back up, I will likely be able to rework it into something decent, but other projects vie for my attention.
Ohh...technically, I DID have another cliffhanger in my much self-ballyhooed "lemon" fic. I was challenged to write one by my good friend and eternal beta reader. However, I was not about to write pure smut without SOME semblance of a storyline, whether it was a false pretense or not.
Anyways, Dante and company ended up fighting demons as part of some great unresolved plot setup, then retired to their office. I then had Vergil kill off the rest of the demons, hinting at a larger story which would never come. Meanwhile, Dante and the ladies were banging the hell out of each other, and my readers all went WTH?!?!?! 
Hearing my beta's reaction the day after was priceless!
Funny thing is, I probably could still continue that story, but I really don't see the point, as it stands just fine as it is. Still, in response to the question, it is a minor cliffhanger.
I did mention Gundam. my cousin introduced me to anime originally and he was like... insanely big on harem anime and giant robot type stuff. he used to babysit us when we were little, and we weren't allowed to watch good movies, so he would bring over "cartoons"... many of which had stuff in them that is a lot more gory/adult/weird than half the movies he could have chosen. but my mom was satisfied just by seeing cartoon-like artwork on the covers. but the point is, chances are if there's a million girls chasing one guy or giant robots in it, I've seen it at some point. *shakes head*
but as I got older I had friends who introduced me to other types of anime, and I gravitated toward that stuff instead. but maybe my cousin is part of the problem. blame him! he killed giant robots for me! *nodnod*
[snip]
I think my fave Gundam was 08th MS Team, as it was the old "Romeo and Juliet" tale, but it was done well. Furthermore, it didn't try to "add a twist" and ruin things. The Tenchi creator is probably among the few harem anime creators I enjoy.
As for harem comedies, or romance in general, I am getting tired of the "baka hentai!" tropes, wherein characters misunderstand and then abuse each other, or leave things unresolved for the sake of sequel-bait. Moreover, I don't generally enjoy slice-of-life rom-coms. They seem to be the craze now, perhaps cheaper/easier to make. Thus, the type of anime I enjoy is being made less and less.
It's funny, I originally got into anime b/c traditionally "western" entertainment was growing stale. After I felt anime following the same tropes, I returned to gaming. Now that few games are made which TRULY interest and compel me (not a big FPS guy, and RPG's are few and far between), I have moved on to reading and writing.