I'm prototyping an old school shooter, too, for some time now that I will work on after my sidescroller and I plan to integrate modern rendering and postprocessing techniques myself, thus I don't dislike the idea at all, but I would either the remove it at all in your case or reduce the strength of the DOF effect noticeably, everything is too blurry, esp. in close rooms, when you play it yourself, it hurts the game.

EDIT: Yes, haha, I did, I was shocked as I shot the sucked up enemy towards the newly spawned group and everyone exploded, but I was amused.