Bullet hits tile. Effect:tile is replaced with another tile

I got 2 tilemaps. One is solid (tilemap), another one is unsolid (tilemap2).

When a bullet is collided with a tilemap, I am trying to do the following

1) The solid tile of tilemap which we hit is erased

2) and is replaced with a tile of unsolid tilemap2 ( I used "set a tile" trick, not sure if it is right).

It drives me mad for over two weeks. I cannot achieve any of these effects while a tilemap is being hit with a bullet.

heliogame

Take a look here:

trying-to-understand-tilemap-collision-detection_t94500

and download this: https://dl.dropboxusercontent.com/u/143 ... t%202.capx (Thanks to RamPackWobble)

That should help...

MultipleChoice, solved! Thank you!