The Fleischer Brother's dark and frankly depressing Superman cartoon shorts from the early 1940's are available to be seen here for free. This was the same studio that created Betty Boop and Popeye. People die and Lois can't go eight seconds without getting into trouble.
The Fleischers were hit or miss but their best work equals Disney's best. I'm a sucker for their "Color Classics" sing-along cartoons, found here. I dare anyone to defy the charms of "The Cobweb Hotel", "Ants In The Plants" ("Make him yell uncle, we'll bust him in the snoot!"), "Small Fry" ("Small Fry, hangin' round the poolroom, Small Fry, should be in the schoolroom"), "The Fresh Vegetable Mystery" ("The yolks on youz guys. I'm hard boiled.") and "Play Safe", which should not been seen on LSD.
They mixed live action and animation, and I always see faces in trees and buildings because the Fleischers anthropomorphized like mad.