Some background on Derain can be found here.
Derain was prolific, so this post features only landscapes to indicate changes in style. So far as I can tell, his paintings always included several of the modernist traits of form distortion, simplification of forms, flattening of the picture plane, and color distortion. The number of traits used and their intensity varied for any given work.
These are early Derain paintings made before Fauvism. Colors are only slightly more intense than they were in reality for the upper painting. At this point, he is mainly simplifying and flattening.
This is a Fauvist painting.
While Derain was fiddling with a few Cubist ideas, he easily dropped back to his pre-Fauve pattern.
Here he actually uses perspective to partly puncture the picture plane, though flatly painted areas mitigate that to a degree.
Painted during World War 2, this is about as close to traditional painting as Derain ever got. Only the foreground simplification suggests his modernist impulses.