It is a cool idea and looks pretty good, tho I have some gameplay complaints to make and some general ones:
-Barrels move too slow, which makes replaying some parts painfully annoying.
-A system for slow and fast movement would be cool, so i don't have to crawl around save parts.
-Shots should not be so inconsistent with their path, the spray is pretty strong which often makes for a stay shot that messes up 3 minutes of pin point precision.
-The Sound Listener should not necessarily be on your camera or the sound producer(the shot sound source on the player) needs to be moved directly to the camera to have consistent audio volume.
-The Sound of the shots is very monotone, and was annoying to me personally, which is very subjective.
-You crosshair should be displayed over all other assets, which it isn't the display order seems to be around this: background>floor>crosshair>everything else while it should be: background>floor>everything else>crosshair
PS.: I like that you can push multiple barrels at once, that's pretty cool