In the film, which debuted on the streaming service earlier this month, Reynolds plays a pilot who travels back in time, meeting himself as a child and his late father (played by Mark Ruffalo).
Zoe Saldana plays his wife, whom he travels back in time to save.
Spoilers follow for The Adam Project...
The film concludes with Adam (Reynolds) having altered the space-time continuum and defeated the villainous Maya Sorian (Catherine Keener).
Before he and his younger self revert back to their own timelines, the pair enjoy a last game of catch with their dad.
Speaking to Collider, Reynolds explained that the moment was influenced by his memories of his own late father.
“All I had to do literally is just look at Mark and feel everything, every unrequited moment I’ve ever had with my own father in real life,” he said. “Truly, I felt so lucky to be working with someone like Mark Ruffalo, who is as good, if not better than everyone already knows him to be.
“And then the catch stuff, that’s all for me is incredibly resonant. That is how I connected with my father. When my father, who’s now been dead for six, seven years, all of my memories that are beautiful with my father are us having a catch on the lawn. That is in the movie, but that’s also true of my real life, which is my dad always had time for that.”
The film’s director Shawn Levy added: “I knew I wanted to not shy away from that catharsis at the end. I like movies that make me feel a lot... So that ending was always built in that there was going to be a goodbye. We were never going to give it a happy ending, but we had to give it an ending with closure and redemption.”
The Adam Project can be streamed now on Netflix.