I'm not sure why some people insist on approaching this series so seriously. It's a boundary-pushing gag manga, and that's all it was intended to be. With how over the top and outrageous it can be at times, I think it's a great success. If the concept doesn't sound appealing to you, then do yourself a favor and just don't read the series.

The story itself makes no real world sense at all, but that's why it's entertaining. It's a bit like Back to the Future (in fact the series itself references the movie with several chapter titles and little winks and nudges here and there), but a little more complicated with its multiple timelines and it will make your head hurt if you try to make sense out of it. Basically, daughters with different mothers from different timelines in the future are in danger of disappearing from existence and are trying to make sure their father chooses their respective mother so that they get born. The story really is not why you should be reading this, but I think it does a great job at giving a ridiculous setting for the ridiculous gags to play out.

The art is pretty good. For a harem-type series, it's relatively detailed and dynamic-looking, but it's nothing amazing and often the panels seem very busy and crowded. The characters' designs themselves don't look like anything too special, but it's easy enough to tell them apart at least for the most part.

Speaking of the characters, most of them fulfill some common archetype. Saku is the loser harem lead, Karin is the childhood friend tsundere, Hiiro is the emotionless kuudere, etc. This may sound like a criticism, but because this is a parody gag series, it really works in its favor.

To expand on that point a bit further, many chapters seem to parody harem and general manga cliches by taking typical plots way beyond what you would expect to see and some of the gags are often a bit shocking, but that's a big part of the entertainment. Giving examples would only spoil the fun the first time through, so I'll restrain myself, but rest assured, you'll be left wondering if the publisher can even legally show some of this stuff.

The series is not perfect, though. Characters will often act completely out of character or become totally Flanderized for a single chapter in order to accommodate a certain story, and although this has an amusing comedic and cartoonish effect, it can feel a little damaging to the characters sometimes. Although the gags in the series are shocking and often gut bustingly outrageous, chapters that focus primarily on gags and move away from the relationships and characterization tend to be a bit weaker.

But those things hardly make this a bad series. Frankly I've really been surprised at just how entertaining I've been finding this series, and fortunately this sort of "ridiculous ecchi gag" thing seems to be the author's forte, so I look forward to seeing more ridiculousness from tenkla/Doi Sakazaki in the future. If you're looking for an ecchi harem series that really pushes the boundaries of what can be shown in a shounen manga or something that makes no sense at all and knows it (in a cartoony kind of way), then you've come to the right place.

EDIT: The series is over now, and my opinion and score remain the same. Without spoiling anything, the ending was downright ridiculous, but at the same time, it's exactly what you'd expect from this series. It was one of the few endings to a harem series I found satisfying, and it does actually wrap everything up neatly. For this, I think the author deserves some credit. She went all the way, and for that, this is a series I won't soon forget. Thanks, tenkla.