i still havent figured out colisions yet
help
most basic 2D collision usually involves having a defined collision 'box' for objects and checking if any collision boxes intersect with one another
ie minX_A < maxX_B, minY_A < maxY_B, and so on (the exact math may differ depending on how the engine works but this is how i've normally done it)
idk how this would change in a top-down perspective, but it would probly just involve boxes that don't necessarily cover the entire object. probly would just be the size of a cell.
actually, pygame has a function that checks the rects for you. maybe love2d has a similar set of functionality?
edit:
appears so lol
http://love2d.org/wiki/Tutorial:Physics