The series is based on comics, so there will undoubtedly be some changes to keep things fresh. However, there has to be some kind of shout-outs that tie directly into the source material and fans love to hunt for those moments. Easter eggs to other series also help give fans little treasures to find while enjoying the series.
Throughout the series nearly any time someone is about to say the name Invincible it will cut to a title card. While this doesn't happen every time it occurs at least once an episode. However, this title card does more than showing the name of the hero and show.
In each episode, there was blood splattered on the title card. As the season progressed there was more and more blood splattered on the card until the final episode where nearly the entire thing was covered in blood. This reflected the amount of violence and gore within each episode gradually increasing.