Sam Rockwell and Anna Kendrick were the only reasons I watched this. Sure enough, they're the only worthwhile parts. Kendrick is fun to watch and very quirky and Rockwell is always a blast. He just has this vibe surrounding him and his own brand of charm is infectious.
Everything else is pretty much a throwaway. The script is weak as there's essentially three sides to a hitman story and all of them were uninteresting. The rom-com aspect is also as basic as you can get.