Snake (Slither.io zoom mod) od Xera

The Snake Extension includes a zoom mod, custom backgrounds, and many other improvements.

Tip: Use the TAB key to hide the UI elements.
Another tip: Use the mouse wheel to zoom in or out.

If you are experiencing issues with your FPS, it is due to the default configuration of Firefox. You can try to fix it:
1. Go to about:config and click on Accept the risk and continue
2. Enter layout.frame_rate above
3. Set the Hz (FPS) value that your monitor supports (-1 is automatic, but unreliable)