The object of Clusterduck is to clear the stage of all the ducks by building cluster chains of same-colored blocks and breaking them with poison blocks. The higher the cluster level, the more blocks it will take to break them. There are three types of blocks; each lends a certain amount of strength to any cluster chain:

  Normal block: 1 point

  Duck block: 2 points

  Poison block: 3 points

Early levels are like shooting ducks in a barrel, but eventually you'll need a game plan and figure out where to stash blocks in an increasingly limited space.

You control one four-block quad at a time, navigating it as it falls. A quad isn’t the most convenient shape, so make the most out of your positioning of colors. Know your command keys!

• Side arrow keys: Moves the quad back and forth.
• Down arrow key: Drops the quad faster.
• Up arrow key: Warp drop, commits the quad to the top of the stack.
• Z and X keys: Rotates the quad.
• Shift key: Makes the quad sticky.
• A, S, D, F, G keys: Activates special attacks.
• Q, W, E, R, T keys: Cancels special attacks.
• P key: Pauses the game.
• M key: Music getting annoying? Turn it off!
• Escape key: Quits the game, of course.
• Enter: "Click" duck shortcut (except title screen).

By nudging a quad against a stack of blocks, you can shift its top or bottom half into nooks or stack single-block columns using one corner of the quad.

When a quad breaks, all of its blocks will fall unless stickied first. A mass of two or more sticky blocks will remain stuck in place, defying gravity. Use the sticky technique to build platforms, but don’t get carried away. Sticky blocks can clutter your space quickly and can also work against you.

Breaking clusters awards points whether you clear ducks or not. You will also be awarded fuel for your special attack gauge. In later levels, simply amassing poison blocks fuels your gauge. (You’ll need all the help you can get!) When your special attack gauge is full and starts flashing, you are allowed to activate one of your special weapons. A small needle will then appear on the gauge as a time limit warning. During this time you may activate a weapon, cancel a weapon, or allow the time limit to expire.

• Activate a weapon: When a weapon is used, its icon will fade out. All the weapons in your menu must be used or canceled before they become available again.
• Cancel a weapon: Sometimes you'll find certain attacks useful while others not as much. If you're in a hurry to reset your weapons menu, you can cancel a weapon you don't need, reset the gauge, and collect a hold bonus.
• Wait it out: Sometimes you'll have no immediate need for a weapon but know it'll come in handy soon given the ducks' aggressive mood swings. Letting the time expire keeps all your weapons intact and awards a hold bonus.

You start with only one weapon at the beginning and earn the others by collecting bonus points. These weapons will become increasingly helpful as the game progresses, and eventually they will be upgraded, too, to meet the demands of tougher levels. Keep in mind that your weapons' cancel keys are right above the activation keys on your keyboard.

  Machine Gun (0 pts, A key): A machine gun appears and fires randomly, destroying all blocks and ducks it hits. Who needs clusters?

  Starburst (300 pts, S key): All poison blocks of the greatest color merge into a single mass, clearing all ducks at ground zero and usually self-destructs. (Will only work if two or more poison blocks of the same color exist.)

  Gravity (800 pts, D key): Gravity waves hit the stage like a tornado, slamming blocks, ducks, and even sticky blocks against all sides of the container walls. Works wonders in earlier levels and is a great counter against "Goo".

  Abducktion (1500 pts, F key): A UFO beams up all blocks on the stage leaving only ducks. Use this when your targets get buried under a ton of mishmash. Work quickly because soon the UFO returns to replace everything it took.

  Termites (2400 pts, G key): A swarm of termites burst from poison blocks in your quad and destroy every same-colored block on the stage. A multi-poison quad can clear the level in one swoop!

With all that firepower at your disposal, the ducks have a bit of unfriendly retaliation. Worse, they’re allowed all their weapons from the start. They, too, have a special attack gauge, which fuels slowly but consistently. As far as what you’re up against, you’ll have to see for yourself.

Bonus points are awarded three ways:

• Letting your attack gauge time-out or canceling weapons gives you a "hold bonus" equal to the level x 10. This bonus then cheapens the longer you stay on that level.
• Clearing clusters of ducks. The more ducks you take out in a single turn, (including chains, machine gun, and starburst) the larger your bonus.
• Clearing a stage using as few quads as possible. The stage bonus for a 100% kill rate is 333, but it is possible to score higher than 100%.

Now, let’s go harm some fowl! Don't get Clusterducked!