I personally don't know how it happened but I was able to finish the first half of the series (at least I think it is the first half) and I have decided to continue watching as this second season opens as a direct continuation of where the first season left off.
Similar to 5D's (which I'm currently watching right now), the first half of the series was more of a prequel to its second half. The main antagonist of the first half, Dr. Faker, was merely a small fraction of the antagonist they are facing right now which is Barian itself.
This season opened up pretty well with the introduction of the problem in hand, a member of what I think is the head of the Barian World goes to earth in order to acquire the Numbers cards which they'll use to destroy the Astral World. As a common trend to the Yu-Gi-Oh! Series, the beginning of this season is a series of duels with duelists that are being controlled by the antagonist.
Comparing this to the first season, the duelists, duels and monsters here are better and I could probably say more decent. Aside from these things being far better than what the first season offered, the additional characters are definitely a nice touch. Of course the idea that they will play an important role later on is still in my mind based on how they are acting.
First off, there's Shingetsu Rei (Hino Satoshi) who was introduced in episode 3 and seems to play the role of being a fan of Yuma. Based on how he seem to observe Yuma's duels, I'm betting that he'll surprise everyone later on in the series. As for the other additional character, Shark's sister has finally joined Yuma's group, Kamishiro Rio (Han Megumi). What's more interesting is that she's a duelist with a pretty decent deck. In addition to that, her glowing eyes gives off a hint that there's something going on within her as well although it's kind of a surprise that neither Astral nor Shark notices it.
Since this is supposed to be another big arc of the series, additional cards or monster types were added. Since last season, XYZ summoning was introduced wherein monsters with the same levels are used to summon an XYZ monster of the same level. The number of monster sacrificed or used to summon the XYZ monster becomes Overlay Units which can be used to trigger the XYZ monster's special abilities or effects. Further more last season, the Numbers were considered as the special type f XYZ monsters and by the end of the season the Chaos Numbers were shown as the leveled-up forms of the Numbers monsters.
This season, since Yuma and Shark has Chaos Numbers, the antagonists of this arc have their very own special card which I see as something similar to Duel Monster's Seal of Orichalcos (although they are still entirely different). ZeXal has this so-called Barian's Force which when activated will rank-up the user's XYZ monsters into Chaos XYZ monsters. In addition, Barian's Force has the ability to absorb the opponent's XYZ monster's Overlay Units and give them to a Chaos XYZ monster. Aside from having an XYZ monster's Overlay Unit being absorbed, they lose 300 Attack Points for each Overlay Unit taken which seems to be quite a lose.
Aside from the addition of Chaos XYZ monsters, I noticed how ZeXal also incorporated the idea from 5D's using monsters for synchro summoning material. In ZeXal, monsters who are used to summon XYZ monsters now have effects. I'm not entirely sure if this was in the first half but as far as I can remember this was not included(:
The art is the same as before, bright and childish. Yu-Gi-Oh! Series's typical character design can still be observed. What's good about this season of ZeXal is the improved monster designs. That's definitely an up for the series.
On some final note, the increase of appearance of both Kamishiro Ryoga a.k.a Shark (Masuda Toshiki) and Tenjo Kaito (Uchiyama Kouki) is certainly a good thing. AND honestly speaking, I still can't get my mind off the fact that they are good rip-offs of the original Yu-Gi-Oh!'s Seto Kaiba (for Kaito since they're both smart and have a younger brother) and Katsuya Jounouchi (for Shark since they both used to be a delinquent of some sort and have a beautiful younger sister). Add to that the really great ED song for the series which I personally enjoy both musically and lyrically (nice going vistlip! Hopefully they'll do more songs for the series :3)
Overall, I personally think that this season of ZeXal won't really be amazing or anything but at the very least, it's nice to see that it was able to top its first season which was pretty horrible. I'm looking forward to seeing this series improve itself with better duels and characters :3
For a review of the first season, drop by here.