It’s pretty faithful in adapting moment to moment scenarios but the order of the moments have been shifted a lot. Like the Mars mission, Robot working with the Twins, Titan and Invincible facing Machine Head, and D.A. Sinclair >!all happened after Omniman left Earth!<.

Then there are some character changes like William already being out of the closest, Amber knowing Mark’s identity for way longer in the show and breaking up with him.