Honestly, I hated it.
I hated it because I really enjoyed it in the beginning but as soon as the antagonist is revealed it all goes downhill. Not sure if they were cut short by the publishers or the writer just gave up. Either way it is bad. I would advise you to just save your time and ignore this manga. Although, I want you to support the artist because the only thing that got me through this manga was because of the art.
Okay, I'll try to explain why the story sucked so much ass without spoilers. The reason for the time machine is SPOILERS!!!
FUCKiNG METEORITES! Which fucks up everyone on earth in later years but it is totally fucking safe to transfer something that stabilize earth from the "primal age" to present as long as it is not "too much". Because a child prodigy that has traveled back in time and lived there for like years said it is fine. Also that child prodigy is the antagonist that doesn't trust in friendship because our protagonist has been tricked to betray him when they were like 5. Our child prodigy antagonist can literally hack into giant rats mind, control electricity and has apparently learned everything about earth's physics... but still doesn't know that if a BLACK-FUCKING-HOLE is created ON EARTH it would fuck everything up instantly and not wait and charge until 2032.
How was this black hole created? Our prodigy here has it already dumbed down for us! It is because of two unknown, unknown. UNKNOWN FUCKING ENERGY from TWO FUCKING METEOR decided to fuck each other and gains MASS. A black hole fucking mass on earth everyone. Yet somehow when our antagonist shows the meteor... guess where he putted it. On a fucking table. Just on a normal godfucking table. I can't get over this... I never expected a full essay of how meteor can fuck up earths gravity theory but this isn't edible in any fucking sense. Why not just ditch the scientific explanation and say magic? Shit like "yeah uhh, earth's spirit like uhh needs help. Apparently a meteor has been stuck in his anus and he wanted some one to pull it out... and yeah it has a lot of electricity and uhh you know you can cancel that shit. Do it pussy."
I have never felt more betrayed. The premise was good I smelled a lot of adventures and good old survival of the fittest. Our protagonist that already had the advantage of never had used any electronics had already lived his life in the wild. Well he couldn't even if he wanted to due to a meteorite. Anyways he lacked in social cues and interactions now has to lead these people that never before had built fire without a lighter. "How will he do it?" Kind of feeling. Yes, it was actually fun the first part of it but yeah as soon as the antagonist pops up he surely fucked up everything. Not much for our protagonist but ME mentally. I felt like it was going to be like Planet Earth shit kind of manga but at the end of the day it shat on me like we shit on earth pretty much.
Anyways that's it for me. Thanks for reading my rant. Hope you had some catharsis from this review if you felt the same as me. Don't forget to support the artists though. He did real good fucking job here. Have a good day/night/month/year or a shitty one if you want. Bye<3