Shake is one of the simplest things you can do.
Just do it your self using variables, the random() expression, and the system scrollx, and scrolly.
+> global variable "shake"= 1
-->system scroll x to scrollx+random(-30,30)
-->system scroll y to scrolly+random(-30,30)
But I would want to have a stable shake (without random):
(I want scrolly first to add VarNum1 pixels and then subsctract VarNum2 pixels)
if shake = 1 --> system scroll y to scrolly+5
--> set shake to 2
if shake = 2 --> system scroll y to scrolly-5
--> set shake to 1
I expected the screen to go go up and down, moving 10 pixels (shake effect). But nothing happened.