the lost wandering in the ashen landscape
I laughed when i read this part.
Btw, wall boundaries are not the best method (In some cases they are) because they allow for skip-through with faster moving objects. A raw coordinate boundary is usually the ULTIMATE SAFEST.
Obj.x < 0 ==> set obj x to 0
Obj.x > right boundary ==> set obj x to right boundary x
repeat for y coords.