I just roped myself and a few other staff members to test this out, and this works perfectly fine from a technical standpoint so I'm happy to release it. But I
do think the ring itself is overpowered.
To be more specific, it's a perfectly accurate weapon that travels
very fast, that tracks the closest target without flaw and you don't even need to aim. You could shoot a ring in the wrong direction and it would turn 180 degrees to make a beeline for the nearest enemy. It's basically a deton ring.
You clearly tried to keep it in line with the other weapon rings by giving it a long cooldown and a very high ring cost, but most of the time you can just pick up your opponents rings after he is hit by the homing ring. And
fire it again before he has a chance to escape and recover. There's no reason to use the other rings, even with the high cost, as it's almost guaranteed to return the rings paid in points and rings your opponents drop.
One of the main reasons for this is because the homing ring tracks the nearst players location perfectly. But the ring would be far more interesting (and less powerful) if it had a turning circle and spent time accelerating after going in a straight line. This would give the target an opportunity to avoid the ring by tricking it into crashing into a wall, or something similar to that. To help illustrate the example, have a gif of Top Down (posted with permission).
Also it really bothers me that you can fire a ring in the wrong direction entirely and it'll still home in on the nearest target.