The first big demo update

Added shadows. The picture no longer feels flat.
The blood system has been improved.
The shadows of the field of vision became softer.
The basic settings for mouse sensitivity and volume have become more comfortable.
The effect of smoke when shooting.
Changing the characteristics of weapons towards a greater difference between different types.
New sounds of enemy death.
Expanded tutorial.
When a player dies, a posthumous message appears.
An assistant in aiming.
The recharge indicator.