I want to make my character bounce back after being hit by an enemy, how do I do this?

Hi imamariobro
It depends on what kind of movement you are using. If it is a simple custom movemet.

Player facing Right
+Bullit overlaps character
+Only one action when event loops
>Character: Set X posion to X player -1

Do the same for facing left, except change X of character +1

Marv

Actually, I don't want him to just flinch back/forward, I want him to slide back temporarily.

How about timer?

Bullit overlaps character
+Only one action when events loop
>Character: set alt value A to 1
>Set timer to 0

Timer is < 2
+ Character is facing right
+ Alt value A of character = 1
>Character: set X position to X position of character -1

Timer = 2
>Character: Set Alt Value A to 0

This will do a slide backwards. You can play around with timer.

Marv