diff --git a/games/boybomb.p8 b/games/boybomb.p8
index 7c99762..df053c7 100644
--- a/games/boybomb.p8
+++ b/games/boybomb.p8
@@ -11,7 +11,7 @@ function _init()
     palt(0, false)
     -- start first scene
     --start_level(1)
-    start_scene("title")
+    start_scene("explainer")
 end
 
 function _update()
@@ -258,7 +258,45 @@ function can_move(dx, dy)
     return true
 end
 
+function explosion_adjacent(x, y)
+    -- called when the block next door explodes
+    local block = puzzle_grid[y][x]
+    if block == BOX_WOOD then
+        puzzle_grid[y][x] = 0
+    elseif block == BOX_FIRE then
+        puzzle_grid[y][x] = GRID_EXPLODE_NEXT
+    end
+end
+
+function process_block(x, y)
+    local block = puzzle_grid[y][x]
+    if block == GRID_EXPLODE_NEXT then
+        add_explosion(x, y)
+        puzzle_grid[y][x] = GRID_EXPLODE
+    elseif block == GRID_EXPLODE then
+        if y > 1 then
+            explosion_adjacent(x, y-1)
+        end
+        if y < GRID_H then
+            explosion_adjacent(x, y+1)
+        end
+        if x > 1 then
+            explosion_adjacent(x-1, y)
+        end
+        if x < GRID_W then
+            explosion_adjacent(x+1, y)
+        end
+        puzzle_grid[y][x] = 0
+    end
+end
+
+
 function update_level()
+    -- bombs break adjacent tiles
+    -- fire boxes turn into more bombs
+    -- goal: break all boxes
+    -- ??? only 8 positions?
+
     -- update grid
     fall_speed = 0.3
     if exploding then
@@ -272,26 +310,7 @@ function update_level()
         last_gravity = t()
         for y=1,GRID_H do
             for x=1,GRID_W do
-                -- explode
-                if puzzle_grid[y][x] == GRID_EXPLODE_NEXT then
-                    add_explosion(x, y)
-                    puzzle_grid[y][x] = GRID_EXPLODE
-                end
-                if puzzle_grid[y][x] == GRID_EXPLODE then
-                    if y > 1 and puzzle_grid[y-1][x] == BOX_FIRE then
-                        puzzle_grid[y-1][x] = GRID_EXPLODE_NEXT
-                    end
-                    if y < GRID_H and puzzle_grid[y+1][x] == BOX_FIRE then
-                        puzzle_grid[y+1][x] = GRID_EXPLODE_NEXT
-                    end
-                    if x > 1 and puzzle_grid[y][x-1] == BOX_FIRE then
-                        puzzle_grid[y][x-1] = GRID_EXPLODE_NEXT
-                    end
-                    if x < GRID_W and puzzle_grid[y][x+1] == BOX_FIRE then
-                        puzzle_grid[y][x+1] = GRID_EXPLODE_NEXT
-                    end
-                    puzzle_grid[y][x] = 0
-                end
+                process_block(x, y)
                 -- fall down
                 if y < GRID_H 
                     and puzzle_grid[y+1][x] == 0