Nullstar.io, like StartBlast.io, is a massively multiplayer asteroid-style game set in a large Slither.io-style world. It's a fun casual game that's simple to learn. There are no complicated menus or ship upgrade paths to contend with. It is completely free to play and requires no download or registration. There are numerous servers available, and players can connect from anywhere in the world. You can also participate in a solo practice session.
Navigate your ship through a dangerous asteroid field using keyboard controls (WADS or arrows). To power your ship, collect "stardust" crystals. To release more stardust, destroy the asteroids (using the Space bar or Shift). Using the H key, you can hyperspace away from danger.