Don't get fooled by the first episode. This show is pretty bad (at least if you expect quality writing out of it).
The main problem for me was the lack of story. They setup a life or death siutation but instead of showing the players coping with it we get a timeskip and a chronological adaptation of the source material (light novels) which means lots of irrelevant side stories. The stakes are mainly ignored and hardly anyone works toward the goal of completing the game (clearing all 100 floors). When the SOA story arc comes to an end it is abrupt and makes no sense at all due plotarmor. The second arc is still airing but luckily it'll be over soon. All changes have been for the worse.
Another issue are the characters; cardboard cutouts and personality changes on demand. Most of the women (or better girls) tend to exist to form a harem for our MC. Speaking of which, this show goes full-shonen as far as his powers go. It is ridiculous what he can pull off (getting his own skills in an mmo, hacking, highest leveled player in the game when all you see is him idlying and helping lowlevel players.. it get's even worse in the second arc).
Given that it is an action show you would at least expect the fights to be good. Unfortunatly these are a letdown. The bossfights usually look rather bad. Not only because of the CGI but the way they animated it. There is hardly a battle choreography and they overuse still frames. You can literally see that the only things animated are the flashing lights which are supposed to represent sword strikes.
Add to this the ever increasing fan-service, silly dialogue, unbelievable romance and countless things that make no sense.

Due to reasons I cannot understand this show is popular and sells really well so a second season could happen.

sp1ti sums it up quite well. This series is overhyped to hell and nowhere near as good as it should have been. So much could have been done with a premise like this but sadly it ultimately fell way short of greatness and wandered into very standard Shounen cliche territory.

It wasn't without it's good points. Despite all its faults I did genuinely enjoy the first half of the series (the Aincrad arc), I just really wish the entire 25 episodes had been spend on this, instead of abruptly ending it at the halfway mark and moving onto Alfheim, at which point all the redeeming qualities of the series fall away one by one and we're left with... well, not much.

Judging by the popularity of the series and the fact there are, to my knowledge, 2 more arcs to go, I'm guessing it's only a matter of time until this gets a second season. I'm not really sure I'll be watching it though.

The art very pretty and the score is beautiful but it went downhill from episode 11 onwards. What a disappointment.

What the hell happened? Everything went so fast from a good TV show to a completely mediocre slice of life in episode 11 then got better in 13, and from 15 to 25 is just frustratingly painful to watch, I would be better off watching endless eight than this second arc.
Btw, I fucking hate Kirito

Didnt know what the show wanted to do there plot was all over the place.

episodes 7 below is not is not connected. the story begins from 8.
this is the good series. i wonder is there a new season until level 100...

sp1ti sums it up quite well. This series is overhyped to hell and nowhere near as good as it should have been. So much could have been done with a premise like this but sadly it ultimately fell way short of greatness and wandered into very standard Shounen cliche territory.

It wasn't without it's good points. Despite all its faults I did genuinely enjoy the first half of the series (the Aincrad arc), I just really wish the entire 25 episodes had been spend on this, instead of abruptly ending it at the halfway mark and moving onto Alfheim, at which point all the redeeming qualities of the series fall away one by one and we're left with... well, not much.

Judging by the popularity of the series and the fact there are, to my knowledge, 2 more arcs to go, I'm guessing it's only a matter of time until this gets a second season. I'm not really sure I'll be watching it though.