Activision’s recent First Person Shooter(FPS) game, Call of Duty: Heroes recently garnered more than 30 million downloads worldwide and to celebrate the great achievement, it will be bringing users a major update that includes an all-new Perk System and Challenge Mode.

The game is available for smartphones and tablets, while letting players take control their own military outpost, forge an army of elite soldiers and build defenses drawn from or inspired by the Call of Duty universe.

Building upon the major 2.0 update introduced in November, version 2.4 of Call of Duty: Heroes will let players enhance their troops and bases with unique Perks, like Override, which increases troops’ offensive power, Stronghold, which bolsters base defenses, and Micromanagement, which optimizes base economy and resource generation. Perks can be earned and unlocked through Helipad Supply Drops, in-game events, or the all-new Challenge Mode.

Challenge Mode introduces a new way to play, wherein players are given a set amount of troops, Heroes, and Kill-streaks to clear a series of seven stages with increasing difficulty. Clearing stages rewards players with resources and Challenge Coins.

Call of Duty: Heroes is available now via the App Store, Google Play, Windows Store and the Amazon Appstore.