Combos
 

Hi, at the beginning, tutorials says something about starting combo when i hit two movement keys simulatenously, could someone explain? becouse i dont get it

It means you must hold down 2 keys at once then hit the attack button...

Hold A,S - W,D etc. - AT THE SAME TIME then press the mouse button. You will see that he throws 2 quicker punches...this is a combo.

Yeah, combos actually really help in this game. If you just punch, punch, and then punch it's slow and leaves you open to attack. If you use combos and do two punches at once then the enemy has to recover longer, giving you more time for even more punches. The only downside is your stamina drains much faster.