All Items in the game are available in both single-player and in multiplayer but with some differences. Read paragraphs Single Player and paragraph Multiplayer.
During the game, Tyler collects useful weapons to destroy obstacles on the grids. Select a weapon with the D Pad of the controller or with the arrows of the keyboard (see controls list). The active weapon will be displayed in the circle at the bottom left of the screen and can be used by pressing the appropriate button.
There are several types of weapons, each suitable for destroying a specific type of obstacle. Here is a complete list of weapons.
The Obstacles are elements present on the grid that do not allow to Tyler to pass and then to be able to color a flow. In the inventory you have the weapons needed to destroy them, but be careful to choose the right one. Obstacles will be more and more present as you advance in the game, even some will be generated by the explosion of some bombs (see "Bombs"). See also page "Game Play" for other informations.
Here is a complete list of obstacles.
Gadgets can be found inside the crates during the game. Always remember to take the Hand Weapon at the beginning of a level in order to destroy the crates. All Gadgets collected will be stored in the inventory visible in the lower left. Selection is made with sticks of the controller or the keyboard keys and the key indicated (see Controls) to use it. Some gadgets have different behavior when playing in multiplayer, so read the section "Items Multiplayer" for more details.
Warning: The gadgets are discharged with the use, except the hand weapon. Once the gadget is completely empty, it takes time to be recharged again and available.
Here is a complete list of Gadgets.
The key appears on the grid as soon as all the streams are completed correctly; you will guide Tyler in finding the right path on the blocks raised and to pick up the key. The Key is not a collectible item; it is only useful to unlock the next level, that's why it is not displayed in the inventory.
Many flows are sunk below the surface by restricting the area of movement. You can raise the floor by activating the levers.
In the Dark World you can find some levers hidden into crates; you need to activate this lever to unlock the next puzzle. Do not forget to use the Teleport or Spawn to gain time.
Destroy the crates with the Hand Weapon in order to find the Gadgets and collect them into your inventory. The Crate appears only in Single Player mode. In Multiplayer mode the gadgets are available in the inventory at the beginning of the game.