It’s worth noting upfront that this series requires a significant commitment from viewers. To truly follow what's happening, you essentially need to have already watched Luke Cage, Jessica Jones, Daredevil, and Iron Fist—each of which is its own lengthy show demanding your attention. That’s actually why it took me so long to get around to writing this review; I simply don’t have the time to tackle all that material immediately. It's a considerable undertaking. However, Netflix did attempt to ease that burden by trying to make it possible to jump into The Defenders without needing to know every single detail from the previous shows. Compared to the comics, where you can get through roughly 15-20 pages of story relatively quickly, television presents more of a challenge. And movies generally don’t require as much background knowledge, especially given that each episode runs close to an hour. Once you clear that hurdle, it's a pretty good show. It would benefit from a stronger antagonist and a more substantial threat to unite the characters. Still, it’s enjoyable enough to watch. Ultimately, the biggest obstacle is just the amount of time required.

Source on TMDB