After payment you will receive an activation key for the Aliens Colonial Marines Season Pass add-on.

You will receive the key in your personal account http://www.oplata.info.
Also, a link to the page with the key will be sent to your email specified during purchase
• ... base game Aliens: Colonial Marines on Steam.

Game description:

You will visit the famous ship "Sulaco" and walk through the cramped corridors of the colony "Hadley's Hope" on the planet LV-426. There you will be able to fully experience the spirit of a dark and dangerous world, where your life can end at any moment.
Aliens: Colonial Marines offers an interesting co-op mode that will allow you to go through the story campaign side by side with your friends. As part of a squad of up to four fighters, each of whom can join the general game and leave it at will.
To cope with the alien threat, you will have to turn into a ruthless and deadly machine, relentlessly destroying Aliens. A branched system of improvements will allow you to develop your character in exact accordance with your favorite style of play.

Activation key:

1. You need to download and install Steam http://steampowered.com/download/SteamInstall.msi (if not already installed)
2. Register a new account on Steam or log into an existing one.
3. Go to the "My Games" section and select "Activate via Steam" and enter the key received immediately after payment.
4. After activation, the game will appear in the list of games and you can download it from steam.