How to get some free Team Fortress 2 hats from free games

You can get some team fortress 2 hats for free from other free games easily as promotional items. I am only talking about free games but if you want to know about all the promotional items for TF2 you can check them here.

PROMOTIONAL ITEMS FROM FREE GAMES

1. Alien Swarm

ITEM : Alien Swarm Parasite

Obtainable by Achievement : 

Hat Trick

Complete 2 co-op missions online. Earns a Team Fortress 2 parasite hat.

2.  Spiral Knights

ITEM : Spiral Sallet

Obtainable by Achievement  : 

Mission Accomplished

Reach the first Clockworks Terminal.