Thanks for the reply
The alien doesn't have drag n drop and it went straight through the wall into the middle of the solid box.
When I run it on mobile, (before I put in the drag n drop and after I removed it just to make the video) they both went, at least partially, through the walls if not completely through the walls.
I don't get it, sprites either go through the walls are get stuck to the walls. It's every game.
How do I get the game to understand that solids shouldn't go through solids?