Review of High School DxD
tl;dr: A high quality show that manages to do well in every aspect, though keep in mind what it's trying to do. This show is incredibly well made, and easily the best in it's genre. The story and characters are legitimately great. Issei is a really good combination of on one hand being lame and amusing but having his heart in the right place and coming through when it counts. Rias too is great in being mysterious and having an air of being larger than life in regards to being the master, but also having more down to Earth problems and interactions with everyone else. Therelationship between the two is especially great, though their relationships with the various other side characters is also well done. As for the plot itself, I thought it was incredibly well paced. It has a solid first arc with multiple parts where things go in random directions at times but that eventually tie together well. The second arc too is well done in that it starts off pretty random, but has good foreshadowing for where it eventually gets to. The twist on this arc was also especially good considering that it was unexpected due to how that's usually not how things go in such stories, but it leads to the finale being perfect. The action and combat also feel pretty well done, in that they don't go that in depth into how everything works yet, but what is shown seems like a pretty solid system. The world building also makes it feel like the story has a lot of potential. And that's not even getting into how it also does a tremendously good job with fanservice, though that could be a negative depending on your point of view.
The good art and animation for everything including action was really well done. It is just all around, from the minor details to larger aspects, really high quality and felt like it was made by people that were putting in a lot of effort and passion. The OP has solid visuals and good instrumental, though I thought the vocals were kind of weak. The ED is a work of art, with great visuals and audio that work perfectly. The soundtrack is solid with a few memorable tracks such as Rias's theme. The sound design overall is good too, with the voice work indicating power ups being perfect. BOOSTO!!!