When a down and out loser discovers a time portal where he communicates with his arrogant younger self, they attempt to create a lucrative future together, but soon become fierce enemies and a battle for control drives him to the brink of psychosis.

Thanks everyone for your advices! This is actually already a finished screenplay wchih I'm trying to option!

be sure to check "O Homen Do Futuro", it deals with time travel, competition between alternatives selves, and there's romance too.

The original logline is too wordy and contains too many descriptions that don't relate directly to the plot. Richiev's version is better but could use cutting of "...but must not destroy his own future."
The implicit danger of terminating himself in the present by killing himself in the past is redundantly reiterated as an additional obstacle to the main one.

"?down and out loser?" is a generic description of the MC what is unique about this character? What is his flaw?
Both of these can make him and his story interesting to watch.

Hope this helps.