In my very first game I got to Rank 6 with 24K points. However, there's some cases where the client and server get out of sync (despite only supposed 10-20ms latency) where the server eventually syncs you with some wild rubber banding. I died because during this rubber banding where I was shoved across the map, I likely was picked off by the leader with 118K points.

Take care of the latency issues and you have the core of something. Something similar-but-different is "Realm of the Mad God" which originally was a Ludum Dare entry using the Oryx spritesheet. So add in some interesting NPCs, and deal with the latency issues and you have the core of something that actually is monetizable.

I did encounter a bug where out of nowhere I was jolted onto the bounds of the map (specifically the lower-left corner) and died, killed by "Unknown".

I think thse bugs in this kind of game are especially scary because you lose everything when you die, which makes you a little weary of starting again. You might get far just to randomly die for no reason. If those are ironed out, I think you've got yourself a pretty good .io game to build upon and keep evolving here!