How do I fix collision in with solid in this project?

Do you mean when controlling with the virtual joystick? Or with keyboard keys?

When using virtual joystick, you should move the tank with 8-direction actions like "Simulate control" or "Set vector", not with "Move at angle" action.

Also, your joystick doesn't work very well, you need at least put it on a layer without parallax. Please see a few better examples of the virtual joystick in this post:

construct.net/en/forum/construct-3/general-discussion-7/collection-demo-projects-149701

For Mobile devices: virtual joystick and for desktop: keyboard

Ok, does this problem happen when you control the tank with the keyboard on desktop?

Ok, I'm tired of trying to tell you that the problem is not with the behavior. The problem is with your joystick code!

I repeat what I told you in my first comment - if you want correct collisions with solids, don't use "Move at angle" action to move your tank. It's not compatible with 8direction behavior!

Only use 8-direction native actions - "8Direction Simulate control" and "8Direction Set vector X/Y". Then your tank will move correctly up and down when touching solid walls.

.

Formulas for "Set vector" actions are:

Set vector X to cos(angle(.....))*speed
Set vector Y to sin(angle(.....))*speed

Disable "Set angle" in event 16, and enable "Set angle=smooth" in behavior properties.

Also, if you want more precise control, use "Set vector X/Y" actions (instead of "Simulate control")