Game is shit

How in the fuck does someone stab a scav in the head with no helmet 3 tiems and the scav doesnt die, but I run up to a t5 kid and stab him once in the head and he dies, or the fact when I close out of the startup it re opens. This game has a lot of bugs other people have stated too and thats the reason this game became a worse piece of shit than tarkov in under a month