Let's recap. The original Railgun was a very light-hearted, fluffy, innocent show with a smiley scene around every corner. Even during battle sequences. Railgun S... is not like that. It's not a bad thing, however. It's good to mature a series with the audience. This series is far bloodier, more emotional and introduces a new band of characters while simultaneously retaining the original ones. The story becomes far more suspenseful with the introduction of Accelerator and ITEM, whose intentions escalate the plot and intensify the darkness factor.
This is one of those anime that J.C Staff have rocked pretty damn well, utilizing flashy and intense animation and effects during battles, even when they're just hand-to-hand combat. The characters are drawn in a way that's common, but still appealing and not too generic. The colorful, glowing scenery of Academy City literally pulls in the viewer into the location presented. The fight choreography is interesting when it comes along, and I found Touma vs Accelerator to be a fight of its' time.
Honestly, when it comes to sound effects, there isn't much to say. They're not garbage or anything, but they are what they are, and they happen to fit the visuals presented. The music is also rather enjoyable, with lots of suspenseful tracks and fitting themes but in all honesty, it's not this anime's forte, and doesn't really hold a candle to some other scores I've heard.
Characters in this are amazing. We have the ever-beloved Tsundere, Misaka Mikoto, her loving companion Kuroko. The awkward Harem king Touma... and then we have the new antagonists which are just as great. Accelerator the sadistic Esper with insane abilities, the deranged leader of ITEM, Shizuri Mugino and her companions. I can go on for days but in the world of RailDex, no two personalities are similar or the same. The development doesn't occur soon, but it does happen later which is a contributing factor to the characters.
I personally enjoyed this anime. The dark shift from its' previous incarnation really stunned me but I adapted to it and it gave the series a whole new theme, allowing more development and progress to occur amidst the chaos. The good old characters never cease to be lovable and it's visually amazing to watch.
Overall, it's a 9/10 for this series.
