There are three impressive set-pieces in this swan song of westerns. The first is a railroad office robbery, and the ensued gunfight, with a lot of civilians killed. The second is a train robbery and the subsequent chase. The final one is a spectacular shootout between Pike's (William Holden) gang and the Mexican troop. The third action scene is just shockingly bloody, and is perhaps the most brutal and violent one in the entire history of American cinema.
The intricate, multi-angle, quick-cut editing of the film "The Wild Bunch" was groundbreaking and revolutionary at that time. And the gritty and nuanced performance of William Holden (Sunset Boulevard, The Bridge on the River Kwai) shows again that he is one of the best actors of all time.