First 5 chapters are just excellent. OP gun fighter, FPS game mechanics as his personal skill, slaughtering of roman-type enemies... but then why does he start looking less and less op? He has the ability to win a war almost single-handedly but an arrow goes past his face and suddenly he's just an advanced long range mage? And he suddenly is afraid because he COULD die here? What about that awesome fight scene where he threw away all thoughts of survival for two little girls? And now they're harem members...
And any limitations that might make the story interesting (other than fear of arrows or magic) are pretty much dealt with when he levels up and gets massively broken OP skills.
Enemy are only fighting because someone more powerful than them will kill them if they don't. Terrible job making the enemy more personal and non-faceless.
Very quickly the author gets over all the old issues that plagued the original group of characters and I don't mean they found solutions to the problem I mean they just forgot about it with mind control powers. Anyone who goes into his space instantly becomes the best ally and that's just the start of the BS. Eventually, the MC gets 1-hit KO powers that work on a % chance system, but are negated when he can just spam it repetitively. And all of the unique ideas that would have taken full advantage of the farm space are forgotten about pretty much instantly. The farming sim quickly goes autopilot and is used for little more than storage space of items, slaves and harem wives.
The entire beastman kingdom arc and F right off.
Changes into your standard meh Xanxia story pretty quick and ruins the whole concept of the story that brought readers to it in the first place.
Basically the ending was similarly as bad as Mass Effect 3's ending. It wasn't a choice for the reader, but it was one of those "did all of this really happen" or something like "it was all just a game the entire time". Honestly those kind of endings are the worst for me because it makes the reader (me) feel like the other red-conned the entire series that you just finished reading.
Bad stuff happening... maybe. Other worlder! I choose you! Go figure it out. Oh, and you're not OP, but very clearly are? Maybe. Its like this, that op-ness is just to get you to normal levels. WHAT?
I thought there was more to the history and background of the first world, but we didn't get exposed enough to it. MC had a history with some of the most powerful and nearly immortal beings in the world, some might even have been considered friends but for some reason both sides take an absolutely stubborn side without any further communication.
Then he becomes a lazy, jobless, shut-in that doesn't want to work or do anything in life other than die after having lived a life of leisure. Yeah he's super powerful, but for some reason lost all ability to play games? And is he powerful or is he intentionally crippling himself to remain "normal" in his/the world's eyes?
Monsters are attracted to MC and every time MC leaves the house new portals are born. Interesting idea that looks like it'll start to rope the MC back into the story. Will he go back to being a kick-ass bad-ass or will he train up the next group of "heroes"?