Unlockables

“

Now that is how it's done! Click to listen — The Sniper on unlocking new items

”

By completing various achievements in Team fortress 2 or select other Valve games it is possible to unlock new items.Some such as the Dead Ringer are simply normal items given to players once the achievement is completed others like the Triclops are rare items only obtainable through an achievement.

Milestone Unlockables

These items are given to players once they complete a set number of achievements for a certain class.They are normal items and can be found via drops or purchased.

Non Milestone Unlockables

Among the many Milestone Unlockables there are also several non-milestone related achievements that reward items to the player once completed such as the Full Head Of Steam.

Non Team Fortress 2 unlockables

There are a variety of Valve and or Steam games that have unlockable items such as Poker night at the inventory which contains 5 items.

Alien Swarm

See also: Alien Swarm (Wikipedia)

Item	Used by	Type	Released	Notes
Alien Swarm Parasite	All classes	Hat	July 19, 2010 Patch	A parasite from the game Alien Swarm, another Valve game. Earned through the Hat Trick achievement in Alien Swarm.