Really good concept - and I always loved and still love the neon artstyle in games :D
Visually and gameplaywise it's a really polished game so kudos for the work!
It was a bit laggy in my browser but my PC is not a fusion-reactor so that was expectable. The controls felt a bit strange at first and somehow I didn't have ammunition and didn't really figured out right away how / where / what.
The multiplayer factor is also good, usually multiplayer games are rare in game jams so it's always a breath of fresh air!