So, I went into this series without any clue...I haven't read webtoon...I directly started watching the series and my god I was invested like crazy since the first ep...
The game setting is very interesting and most importantly, it is well executed...given it's budget, series surprisingly executed almost every aspect flawlessly...for me, the series is 9.5/10 overall but...I added 0.5 because they deserve the praise for making such a beautiful series within limited budget...

Pros:
-there is no toxicity: every character is lovable and understanding...the love triangle situation is handled in a very mature way...
-acting: Lee taevin gives a standout performance here, he needs more work ASAP...
Other actors also did so well...it's very believable...
-story: the storyline is a rollercoaster ride... continuously oscillating between darker and deeper and themes lovey dovey elements...last two ep will make you cry...and all the cute moments will make you blush hard...also, the final takeaway of self love is unexpected but worth it...
-music: the music choices are well thought and elevate the overall feel...
-production and cinematography: the series looks high budget...the frames capture it's youthful nature perfectly...

Cons:
-screenplay: it could've been better.. if this had atleast 10 ep, the game and system error elements could've been explained in a better way...I wouldn't say it is bad...but it does confuse you frequently because the cuts are abrupt without any explanation...but maybe it can make sense if you consider it's game premise, thinking it might be because of glitches...

Overall, it's a must watch, not just as a bl but even as a general kdramas...This is a classic that will be remembered in years to come...
Definitely in my top three kBLs...(along with the eighth sense and to my star 2)