Now, disregarding the dissing below… this series is actually very interesting, which I have to say surprised me as I normally avoid isekai like the plague.
Although it's not the first webtoon that uses landscape photos as background, I don't think I've ever seen it used this effectively. This series is absolutely gorgeous, a feast for the eyes. And not only that: I read the Toomics paywalled version, and you'll see the author has a great imagination for monster design. Maybe I haven't been looking in the right places (I'm sure isekai enthusiasts must have seen all sorts of designs, bland and original), but one of the next enemies has a stunning design.
As for the story itself… definitely not a self-insert. I won't go into details not to spoil anyone, but his ping-pong between both worlds alters the dynamics completely from a garden variety isekai (and I did try a few before abandoning the genre as hopeless, though of course there must be others in which this also happens). His OP status doesn't make him less pitiful, and the plot is currently (chapter 23) branching out. Of course, OP status can disrupt a plot and make it uninteresting, but so far it hasn't happened. (And believe me, I hate OP heroes in general.)
The humour is also spot on. It offers relief when needed, and doesn't interfere with the more serious aspects of the story.
Characterisation begins so-so, but gets much better later on.
This isekai is a pleasant surprise. Right now, I'm completely hooked.
Kudos to Hatigarm for scanlating it even though Toomics is far ahead. However, they may yet catch up: Hatigarm is following the Korean version, which is chopped into smaller chapters by Toomics. The events in chapter 3 here reach chapter 5 in Toomics, so later on it's possible that this will be the place to come for the latest episode. Toomics' translation is better on average, but not by much, and Hatigarm's version of the first couple chapters is the one I prefer.
(And I do hope they catch up, I'm only subscribing to Toomics because of this one series.)
I have high hopes for this one.