I figured I would add a review to try and help spark interest in Re:Library's excellent translation of this. Just marathoned all 290+ chapters that are currently translated, and I really enjoyed all of it.
First of all: this is pretty unrealistic, and is clearly just for enjoyment. Don't read this and expect to nitpick about all the ridiculous [chinese webnovel] cliches and so on. For example, he codes BY HIMSELF Windows 97 from memory in 1995 (using future knowledge). In. A. Month. The he sells it to Bill Gates and promises to work on the next one together. See? Utterly ridiculous. That being said, much of the 'early' adventures are him making ridiculous business deals to build up capital so he can just toss money around the rest of the story.
So again: don't expect realism. It is totally enjoyable if you are willing to suspend disbelief! The webnovel is basically his first year of highschool (age 16) with a 31 YO's memory, on assorted arcs dealing with business, saving random girls, wooing random girls, and having a wife-approved harem. Seriously, he dies because of a single girl, and within... 40 chapters?... he's already wooing others. All COMPLETELY supported by that one girl! (She's the 'head wife', and controls the mistresses lol). No real NSFW scenes (i believe they were deleted by the author), but sex is constantly going on in the background, so be advised.
Anyway, if you're ok with some major suspension of disbelief, the MC is a really good one from a WN perspective, as he doesn't ever assault innocents, and hasn't killed a single person. That being said he's a superman, general pervert, super overpowered, has super memory, makes millions as a 16yo, etc.... but damn if it isn't fun.