Sigma Team started working on it right after release of AS2, taking into account the players' wishes:
Player upgrade parameters simplified.
You will use powerful military equipment to eliminate advancing enemy troops. As the game goes on, you will upgrade your weapon in different ways, and the right choice will let you win the battle!
About 10,000 monsters on each map, showing up to 100 monsters simultaneously on one playing screen
Arcade action combined with sophisticated RPG elements
Many hours of game play with 17 missions
3 game modes: Campaign, Survive and Gun Stand
And, to crown it all, dynamic music and sound effects
Natural phenomena (fog, rain, water)
A variety of playable characters, each featuring unique abilities
Character upgrade facility
More than 50 types of weapons - now you can not just kill but also burn, freeze and even diminish the enemies
More than 20 types of handy gadgets - from flare guns, radar and medkits to battle drones and much more
Red or Green blood selection
Highly imaginative selection of enemies
Reactive music which helps to drive the action
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Two new missions added.