make scene like metal slug

how to make scene same metal slug by actor cannot walk back scene (scene that actor has pass walk)  thank

If you wanted to do something like the original Mario bros, where you cannot move the screen leftwards, you can always place an invisible actor wall at that side like an HUD and move it as the camera moves.  This also works if you just want to stop them from going backwards off the stage...

I honestly hope that's what you want, since your sentence is hard to understand (and I've never played metal slug).

In your movement coding, don't allow for the player to go beyond the x of the camera when walking backwards.