After big cataclysms on Earth, cities were destroyed. People went to live in the catacombs, or well-protected villages. The cities were occupied by mutated people. You are a researcher of these abandoned cities. Weapons and ammunition are highly valued now, so you have to go to the abandoned cities for ammunition. Kill monsters and collect weapons.
Control keys:
F - Pick up weapons, ammo
1,2,3 ... Change weapons
WASD - Character movement
SPACEBAR - Jump
SHIFT - Sprint
Esc - Exit to the menu
LKM - Shoot