The strong powerful music, the use of 60s's-style typing and tempo, the visually explicit violence, and the "inspiration" from other movies are all Tarantino trademarks present in this movie.
The script is not as brilliant as Kill Bill, and reminded me more of Reservoir Dogs in its tone and style, but the film is truly entertaining, thrilling and captivating at times, obscure and pointless sometimes. It has, in a way, the playful mood of a the Great Escape, with a bit of comedy, drama, adventure, violence and little bit of romance added here.
There are not good or bad people in this movie, all are nasty in different degrees. The "basterds" are extremely violent and inhuman, which somewhat dilutes their good intentions of fighting inhuman violent people. If you are as cruel as the cruelest person, you are not better than them, even if your principles and aims are very different. On the other hand, German soldier Zeller, despite killing 300 soldiers in battle, does not enjoy or feels proud for doing that, which makes him more human than any of the basterds. The Jews-hunter is very clever and likeable, more than any of the basterds who are less clever, more naive and idiotic than this sophisticated German.
In many scenes, the violence is justified, but in others is not. Although this is quintessential Tarantino, by treating all moments with so much explicit violence, the tone and tempo of the movie get diluted; if Tarantino had dosed the violence in the film, leaving some of it for the dialogues, the spectator would have been less overwhelmed visually, and the film would have been more balanced.
Most of the main actors are good in their respective roles. I especially liked Christopher Waltz as the ruthless Jews-Hunter, Daniel Bruhl as sweet soldier Zoller, Diana Kruger as the hot spy, and Mike Myers in his little cameo. Brad Pitt is OK in his role, but I find his facial gesticulation over the top, and truly annoying. On the contrary, Melanie Laurent is too hieratic and emotionless in her performance. Some of the secondary roles and actors are almost caricature-ish, so one does not know if this is a demand of the script or the actors not being specially inspired in their respective performances.
I consider the ending a big flaw. It can be understood as a projection of the Universal unconscious, but it lacks fictional verisimilitude not just historical one. This fictional licence rests credibility to the story and puts a sort of childish ending to a film that is not bad.
Despite its shortcomings and not being Tarantino's best, Inglourious Basterds is a very entertaining film that makes good points about the nature of violence, has an overall good cast, and has some good performances.
