This would make an amazing TV Series.
I was imagining this as a gritty TV series in the vein of Breaking Bad/True Detective.
Two Hitmen take on contracts, and take a journey through the crime underworld and take on all of the people therein.
The Hitmen are of course villans themselves, but not as bad as their targets.
So take this film, ignore the final third of it, and make it a TV series. I don't know if they'd even allow it on telly, but it would be amazing.
Keep the cast the same, anyone else would be *beep*