Defiance - An open-source multiplayer 2D shooter game in Java.

Defiance - An open-source multiplayer 2D shooter game in Java.

Over the past week or so, I have worked diligently modifying the Sydney Engine multiplayer shooter game, written in Java originally by Keith Woodward in 2008, using the Apache Mina networking framework (version 2.0.9). I’ve added a boatload of new features, and improvements, including HUDs, particles, new weapons, and greatly improved the chat system, as well as killstreaks and so forth. I’m now putting it on github, and I hope someone could look at it and find a bug in the internet system.

Version 1.0.1


Grab the .jar file and play now! : Defiance.jar


Setting Up and Playing

Dependencies: The jars are included in the SydneyDependencyJars folder. Just load the Eclipse Project, and run the class.

======[ Controls ]======

  • Move with Arrow keys or W, A, S, D
  • Left mouse click: fires weapon
  • R: reloads weapon
  • Number keys (1-9) or Q/E or Mouse wheel: selects available weapons
  • `[funny key above TAB]: turn on/off player names and hit points
  • Enter or Shift & Enter: Activate chat, then and once you’ve typed the message, press enter again to send. If shift is down when you first press enter, the ‘send to allies’ option is ticked
  • Page up or down: zoom in/ out
  • Escape: displays menu.

======[ Weapons ]======

  • Pistol - Basic weapon with low damage.
  • Machine Gun - Standard rapid-firing rotating gatling.
  • Flamethrower - Close-range weapon that sprays napalm that will stick around for a while, useful for area denial. The napalm will cause damage to anyone that walks over it.
  • Shotgun - Dual-shot weapon that fires a cloud of pellets. Most effective at close ranges.
  • Sniping Rifle - Accurate for long-distance one-hit kills, but slow-firing.
  • Tranquilizer Gun - Fires in short bursts, stunning enemies and slowing them and making them unable to fire.
  • Rocket Launcher - launches rockets that have a large explosion radius. More damage is dealt to objects that are closer to the epicenter of the explosion.
  • Homing Gun - launches three alien-technology orbs that will fire like a regular bullet unless there is an enemy in front of it, in which case it will automatically follow that target. The orbs are relatively slow, but are still useful around corners and against dug-in defenders.
  • Nail Gun - An alternative to the machine gun, that spits out 3 nails at once very rapidly, but watch out for your ammo depletion, since it comes with a small clip considering its rate of fire.

Both the Flamethrower and the Rocket Launcher are Variable-Range weapons, that is, their bullets can detonate or stick at a certain range away from the weapon by using the mouse to aim.

======[ Items ]======

  • Healthpack - Restores 33% health.
  • Godly Armor - Grants invincibility against all weapons for 15 seconds, but player can still be tranquilized
  • Speed Shoes - Significantly speeds up travel.
  • Invisibility Shroud - Enemies can’t see and target you for 15 seconds.

You can only use one of either the Godly Armor or the Invisibility Shroud, but not both. But, the Speedy Shoes can be used with anything.

======[ Extra ]======

The wi-fi on laptops may cause noticeable lag over local LAN, but still very playable.

This was slightly modified from the excellent Sydney Engine v. 0.2, made by Keith Woodward, whom can find me on the forums at or contact through . If you’d like to expand on this game, you can download the source code of Sydney Engine on, just search for ‘SydneyEngine’.

I have a small list of todos:

Fix internet gameplay, make networking more dependable
Achievements??? - 1st kill, 3rd, 10th, 20th, 30th, 50th, 75th, 100th, 150th, 300th, 500th kills Die 1 time, Die 3 times with no kills, Get 3 healthpacks, Get 3 invisibilities, Switch weapons 20 times, used each weapon at least once, killed with each weapon at least once, assist 25 times
Make personal pop-up alerts configurable
Enhance graphics
Mech Suits support?
Destructable walls- possibly by using subtractive polygons
Map Editor/Maker!


Feel free to clone or fork it on github and all contributions are welcome.

Are there any suggestions or comments about this? Does anyone have any suggestions for improving the vector graphics?