This is a fantastic game! I love the movement options the grappling hook opens up! A few things:
1) The server "kill feed" can get backed up with entries sometimes. Once that happens, it's very easy as a player to get a kill, look up, and see that " owned X" instead of "Player owned X".
2) Have you considered adding a slide/roll or allowing players to hook on to the ground as well? There are certain situations where I want to zip along the ground (bit like a dash) and reposition behind my opponent. Not a terribly big deal because I can hook onto an object behind them but the rope gives them an easy way to line up a shot.
Great job!