It starts really well but it ends up becoming the typical battle shounen with exaggerated powers and asspulls.

I keep hearing this series was axed, and if that's true, all I can say is bringing it back would be better than most of the new stuff coming out today.

Yeah, Ageha (the main character/MC) can be a bit frustrating to read with how emotional his decisions are, but for the most part his characterization is solid and he's a mostly respectable character.

And I don't think there's an explicitly revealed reason for the villains' motovation. But, considering

the main villain was a human experiment who started talking with a thing inside a meteor or comet from a young age, I suspect he was convinced by the thing to do what he did therefore there is a reason... I think. But it's not exactly satisfying.

Still, the story handles its characters, settings, plot and dialogue very well. And the art, while not extremely good, is still better than average overall. I want more like this and less of the inane, cutesy slice-of-life and lazy isekai manga.

But the end is rushed/not good.

I have reread this series for the third time, it's more amazing than ever after I have reread a few other shounen series like One Piece, Nanatsu na Taizai, Onepunch-man, Boku no Hero Academia and so on.

I like this series because while there are inconsistencies here and there like Ageha's powers and personalities (yes he too has the sudden power up syndrome) and the ever existing time paradox, the series is quite progressive (and also a bit draggy) in showing the aftereffects of the present contributing to the future. And more importantly, in a shounen series, normally romance is not touched so much upon, but this series not only progresses the main characters' romance, the side characters' romance, but even for the villains. The author is simply amazing in storytelling, no doubt.

Some reviews say the ending is rushed because it was axed, well I am amazed. It is still so amazing, I can't tell that it was rushed or axed. Look at Mx0 and Double Arts for reference.

Regarding the originality of the series, it does feel very Gantz-life in the beginning. But Gantz's story is very messy and initially, the first MC is more like a villain than a protagonist. But Psyren does this right from the beginning. And expounds on it with the plot following from his initial intentions and behaviour, before expanding into more plot. In this sense, the plot is really progressing from his one single action towards the end. And along the way, it also branches into several common shounen scenarios, such as friendship.

Overall, I would say this is a great series, I love how most of the characters have distinct personalities that further the plot naturally, rather than incident-based. A series I find it similar in this aspect is Angel Densetsu, even if the genres are very different.

Main problem here is the lack of motive for the actions the WISE take, it just makes no sense. Also, not having feeling doesn't make you a mass murderer. What's the justification for wanting to erase humanity from the face of the earth?? Supremacy is "understandable" but eradication?
In short, the setting is nice as is the initial idea but the mangaka made the chars way too shallow, it's hard to take things seriously like that, making everything lacking in sense and rather forceful. And when they try to make some sense of it towards the end it just seemed to me like a load of bull... so the plot development is also weak.
Other than that is a VERY generic manga with no particularly redeeming points.

I started reading this manga thinking it would be a purely Play or die type of manga ( similar to Gantz/ Bloodie Junkie). But the stories soon goes into a different and much more complicated direction. It was not what I expected however still an excellent series.

Some of the weakness of the series came from the fact that it was cancelled, thus the later half was rushed.

the final battles are highly anti-climatic, characters potential were not fully realized, supposedly main characters disappeared for arcs just to come back in the end to help fight the mini villain squads, ridiculous power invention and power upgrade. Despite all of this, the final ending manage to be very satisfying. I find the solution the author had for the big problem ( how both worlds were saved, MC rescuing #7, the W.I.S.E left instead of having a quick heel-face-turn) was near perfect. However, since the characters were really interesting and engaging, I hope there was some epilog of sort that depicts their life afterwards.

the end was rush because he was force to end it by the deadline shounen jump put them to.
beside this manga is one of my favorite such a waste to end it all Y_Y

A lot of it feels like like it's made up of temporary ideas that failed to stick and it fails to build a consistent world with a focused story. It starts as a game, then it becomes a story about time-travel, but the implications of time-travel are largely ignored, characters and situations that don't go anywhere appear, plot lines are discarded and then hastily resolved at the end. The main character is practically a blank slate - completely unappealing. It's not that he's unlikeable, it's that his personality is not even there and he doesn't even seem to be relevant to the plot. If he'd have had more presence, perhaps this series would have been more than just a mediocre action manga.
The series was canceled due to lacking popularity and I can sort of understand why that would happen - the pacing of the story was abrupt and the characters don't really make an impression.

First volume was boring as its attempting to introduce suspense. It gets interesting starting around volume 2.

Basically, like Gantz, their ears starts to ring, then they are teleported to another world and when the phone rings, the game starts. after they kill the monsters, they are teleported back. Each trip will earn points. But the rules are loose, and characters have no reason or motivation to fight at all. The games repeat, the story progresses, and the mistery builts up. Who's doing all this, and for what reason?

Around volume 8~10, it starts to ramble on and on.

Time traveling, parallel worlds, psi powers, these are pretty interesting. But when the author starts to introduce multiple personality disorder, aliens hidden inside a comic, that sounded like someone's pulling ideas out from their azz. And where is that cute ghost girl that every pop manga seems to include?

Overall, this would have been a classic time traveling manga had it ended around v10. But more became less and the result was unsatisfactory.

I enjoyed this series from start to finish. Many people complain that this is a typical shounen manga, but what's wrong with that? Especially if it's shounen done very well. My only complaint is the rushed ending, but that's to be expected as the series was axed by WSJ :S