diff --git a/res/tower_howitzer_icon.png b/res/tower_howitzer_icon.png
new file mode 100644
index 0000000..3e914a3
Binary files /dev/null and b/res/tower_howitzer_icon.png differ
diff --git a/src/game.lua b/src/game.lua
index 4d02ee5..40c6981 100644
--- a/src/game.lua
+++ b/src/game.lua
@@ -17,7 +17,8 @@ local TRDTS = {
 local function get_initial_game_state(seed)
     local STARTING_MONEY = 50
 
-    local map, world = random_map(seed)
+    local map = random_map(seed)
+    local world = make_hex_grid_scene(map)
 
     return {
         map = map,              -- map of hex coords map[x][y] to a 'tile'
@@ -104,7 +105,6 @@ local function game_pause()
 end
 
 local function game_deserialize(json_string)
-    -- @TODO decode from some compressed format or whatever
     local new_state = am.parse_json(json_string)
 
     if new_state.version ~= version then
@@ -112,7 +112,8 @@ local function game_deserialize(json_string)
         return nil
     end
 
-    new_state.map, new_state.world = random_map(new_state.seed)
+    new_state.map = random_map(new_state.seed)
+    new_state.world = make_hex_grid_scene(new_state.map)
     new_state.seed = nil
 
     for i,t in pairs(new_state.towers) do
@@ -190,7 +191,6 @@ local function game_serialize()
         end
     end
 
-    -- @TODO b64 encode or otherwise scramble/compress
     return am.to_json(serialized)
 end
 
@@ -640,7 +640,6 @@ function update_money(diff) state.money = state.money + diff end
 function game_end()
     state = {}
     game = false
-    -- @TODO anything
 end
 
 function game_save()
diff --git a/src/grid.lua b/src/grid.lua
index 3fc93f6..f884bb5 100644
--- a/src/grid.lua
+++ b/src/grid.lua
@@ -172,8 +172,8 @@ function map_elevation_color(elevation)
 
     else
         -- @TODO probably fix... this only happens when loading a save, and the tile has an elevation that's
-        -- higher that anything here
-        return vec4(0.1)
+        -- higher that anything here. it isn't really of any consequence though
+        return vec4(0)
     end
 end
 
@@ -258,6 +258,6 @@ function random_map(seed)
         end
     end
 
-    return map, make_hex_grid_scene(map)
+    return map
 end
 
diff --git a/src/mob.lua b/src/mob.lua
index bf2bbaf..46fdc18 100644
--- a/src/mob.lua
+++ b/src/mob.lua
@@ -7,7 +7,7 @@ MOB_TYPE = {
 MAX_MOB_SIZE = hex_height(HEX_SIZE, HEX_ORIENTATION.FLAT) / 2
 MOB_SIZE = MAX_MOB_SIZE
 
-MOB_SPECS = {
+local MOB_SPECS = {
     [MOB_TYPE.BEEPER] = {
         health = 30,
         speed = 8,
@@ -33,9 +33,7 @@ local function grow_mob_health(mob_type, spec_health, time)
     return spec_health + math.pow(state.current_wave - 1, 2)
 end
 local function grow_mob_speed(mob_type, spec_speed, time)
-    -- @TODO maybe speed shouldn't grow with time at all.
-    -- if it does, a small amount with a horizontal asymptote
-    return spec_speed
+    return spec_speed + math.log(state.current_wave + 1)
 end
 local function grow_mob_bounty(mob_type, spec_bounty, time)
     return spec_bounty + math.pow(state.current_wave - 1, 2)
diff --git a/src/tower.lua b/src/tower.lua
index c4bb802..59753f6 100644
--- a/src/tower.lua
+++ b/src/tower.lua
@@ -12,7 +12,7 @@ TOWER_TYPE = {
     LIGHTHOUSE = 6
 }
 
-TOWER_SPECS = {
+local TOWER_SPECS = {
     [TOWER_TYPE.WALL] = {
         name = "Wall",
         placement_rules_text = "Place on Ground",
@@ -31,7 +31,7 @@ TOWER_SPECS = {
         short_description = "Fires area of effect artillery.",
         texture = TEXTURES.TOWER_HOWITZER,
         icon_texture = TEXTURES.TOWER_HOWITZER_ICON,
-        cost = 20,
+        cost = 30,
         range = 6,
         fire_rate = 4,
         size = 0,
@@ -79,7 +79,7 @@ TOWER_SPECS = {
         short_description = "Attracts nearby mobs; temporarily redirects their path",
         texture = TEXTURES.TOWER_LIGHTHOUSE,
         icon_texture = TEXTURES.TOWER_LIGHTHOUSE_ICON,
-        cost = 20,
+        cost = 70,
         range = 7,
         fire_rate = 1,
         size = 0,
diff --git a/texture.lua b/texture.lua
index 730e7b7..44043fe 100644
--- a/texture.lua
+++ b/texture.lua
@@ -65,7 +65,7 @@ function pack_texture_into_sprite(texture, width, height, color)
         y1 = 0, y2 = height, height = height
     }
 
-    if color then sprite.color end
+    if color then sprite.color = color end
 
     return sprite
 end