diff --git a/games/boybomb.p8 b/games/boybomb.p8
index 2c4db36..f1a417b 100644
--- a/games/boybomb.p8
+++ b/games/boybomb.p8
@@ -201,30 +201,32 @@ function update_level()
     end
     if t() - last_gravity > fall_speed then
         last_gravity = t()
-        for y=GRID_H,1,-1 do
+        for y=1,GRID_H do
             for x=1,GRID_W do
                 -- explode
                 if puzzle_grid[y][x] == GRID_EXPLODE then
-                    if y > 1 and puzzle_grid[y-1][x] == GRID_BOX then
+                    if y > 1 and puzzle_grid[y-1][x] == BOX_FIRE then
                         puzzle_grid[y-1][x] = GRID_EXPLODE
                     end
-                    if y < GRID_H and puzzle_grid[y+1][x] == GRID_BOX then
+                    if y < GRID_H and puzzle_grid[y+1][x] == BOX_FIRE then
                         puzzle_grid[y+1][x] = GRID_EXPLODE
                     end
-                    if x > 1 and puzzle_grid[y][x-1] == GRID_BOX then
+                    if x > 1 and puzzle_grid[y][x-1] == BOX_FIRE then
                         puzzle_grid[y][x-1] = GRID_EXPLODE
                     end
-                    if x < GRID_W and puzzle_grid[y][x+1] == GRID_BOX then
+                    if x < GRID_W and puzzle_grid[y][x+1] == BOX_FIRE then
                         puzzle_grid[y][x+1] = GRID_EXPLODE
                     end
-                    --puzzle_grid[y][x] = 0
+                    puzzle_grid[y][x] = 0
                 end
                 -- fall down
                 if y < GRID_H 
-                    and puzzle_grid[y][x] == GRID_BOX 
-                    and puzzle_grid[y+1][x] == 0 then
+                    and puzzle_grid[y+1][x] == 0
+                    and puzzle_grid[y][x] != 0
+                     then
                     puzzle_grid[y+1][x] = puzzle_grid[y][x]
                     puzzle_grid[y][x] = 0
+                    -- crushed, explode
                     if y+1 == bomb_y and x == bomb_x then
                         explode()
                         puzzle_grid[y+1][x] = 0
@@ -283,7 +285,12 @@ _scenes.level = {start=nil, draw=draw_level, update=update_level}
 
 GRID_W = 8
 GRID_H = 9
-GRID_BOX = 137
+BOX_WOOD = 137
+BOX_STEEL = 138
+BOX_FIRE = 139
+BOX_FROG = 140
+BOX_NUKE = 141
+BOX_WATER = 142
 GRID_EXPLODE = 76
 
 animations = {