Update: major changes in gameplay, new graphics and sounds

What's new:

• Brand new game mechanic: crowns (previously known as "targets", now internally called "collectibles") need to be picked up and transported to portals ("drop zones"), which appear after a pickup is made. If a player carrying a collectible dies, any player can pick up the collectible and take it to the drop zone and get the point. At this point there are 4 portals on each level (near each corner); a random portal will activate after each pickup.
• Players can now throw their weapons: thrown weapons can kill enemies or other players for a short period of time and will disappear (can not be picked up after thrown).
• Boxes will re-use their spawn locations infinitely, there are no more box drops from above.
• Dropped weapons can be picked up if they have ammo left in them (if not, they will disappear).
• Spikes now extend/contract every 10 seconds.
• 3 new player graphics, assigned randomly at each spawn.
• New background image (desert); background images are chosen randomly at the start of the level.
• New sound effects: shotgun fire, mine bounce, grenade bounce, grenade explosion.

There's a very good chance that there are a bunch of new bugs due to the major changes to gameplay and internal refactoring, so feel free to report them :)