Ok I have a 64x32 base icon and i've been told that since Byond isnt 100% functional with this system that the top half of the base wil be unrecognized by mobs and such and will be passed through. Now i do not want projectiles flying through a persons head without them taking damage, but i also don't want to half to split everything into a bottom and top because i've seen games do that and what happens is that the top half doesnt always appear. If you have a coding solution or just some advice i would love to hear it.
Just check if the location of the projectile is one y above the the multi-tiled mob.
In response to Ulterior Motives (#1)
SO its possible for it too still work? We just have to make sure the projectile hits the top part is that what your saying?
In response to Fantasie Productions (#2)
As the projectile moves check it's location. Check to see if a mob is in the location, or the location directly below it. Then call your damage procs, or whatever.