Ninja io is one of the best arena battle io games. Ninja skill will help to win the other players :)
How to Play
There're 2 modes: Deathmatch and Capture the flag. Main goal of the first is to receive as many kills as possible till the time is out. In the Capture the flag mode you win when you have captured and brought to your side more flags then your opponents.
When the game starts you're asked to select a weapons: primary and secondary.
Extra you're given 3 shuriken + may grab some grenades on the map. Use them with E key.
There 3 bars that reflect you health, energy (required to fly) and ammo (charge).
You can a kind of fly using energy, right click to fly. Consumes energy very fast, but it recovers fast as well.