diff --git a/source/component/plant.py b/source/component/plant.py
index 828d161..32b244b 100755
--- a/source/component/plant.py
+++ b/source/component/plant.py
@@ -48,7 +48,7 @@ class Bullet(pg.sprite.Sprite):
         self.rect.x = x
         self.rect.y = start_y
         self.dest_y = dest_y
-        self.y_vel = 4 if (dest_y > start_y) else -4
+        self.y_vel = 15 if (dest_y > start_y) else -15
         self.x_vel = 10
         self.damage = damage
         self.effect = effect
@@ -107,7 +107,7 @@ class Bullet(pg.sprite.Sprite):
     def draw(self, surface):
         surface.blit(self.image, self.rect)
 
-# 暂时是杨桃的子弹，以后可以扩展到非定行飞行的子弹
+# 杨桃的子弹，看作豌豆、孢子类子弹的特殊子类
 class StarBullet(Bullet):
     def __init__(self, x, y, name):
         self.name = name
@@ -324,11 +324,12 @@ class RepeaterPea(Plant):
 
 
 class ThreePeaShooter(Plant):
-    def __init__(self, x, y, bullet_groups, map_y):
+    def __init__(self, x, y, bullet_groups, map_y, background_type):
         Plant.__init__(self, x, y, c.THREEPEASHOOTER, c.PLANT_HEALTH, None)
         self.shoot_timer = 0
         self.map_y = map_y
         self.bullet_groups = bullet_groups
+        self.background_type = background_type
 
     def attacking(self):
         if (self.current_time - self.shoot_timer) > 1400:
@@ -337,7 +338,10 @@ class ThreePeaShooter(Plant):
                 tmp_y = self.map_y + (i - 1)
                 if tmp_y < 0 or tmp_y >= c.GRID_Y_LEN:
                     continue
-                dest_y = self.rect.y + (i - 1) * c.GRID_Y_SIZE + offset_y
+                if self.background_type in {c.BACKGROUND_POOL, c.BACKGROUND_FOG, c.BACKGROUND_ROOF, c.BACKGROUND_ROOFNIGHT}:
+                    dest_y = self.rect.y + (i - 1) * c.GRID_POOL_Y_SIZE + offset_y
+                else:
+                    dest_y = self.rect.y + (i - 1) * c.GRID_Y_SIZE + offset_y
                 self.bullet_groups[tmp_y].add(Bullet(self.rect.right  - 15, self.rect.y, dest_y,
                                                      c.BULLET_PEA, c.BULLET_DAMAGE_NORMAL, effect=False))
             self.shoot_timer = self.current_time
diff --git a/source/constants.py b/source/constants.py
index c0da0a7..064e3e1 100755
--- a/source/constants.py
+++ b/source/constants.py
@@ -46,8 +46,6 @@ PURPLE       = (255,   0, 255)
 GOLD         = (255, 215,   0)
 GREEN        = (  0, 255,   0)
 
-# SIZE_MULTIPLIER = 1.3 # 没有用
-
 # 退出游戏按钮
 EXIT = 'exit'
 # 当想要一个特殊值时用
@@ -76,6 +74,7 @@ GAME_LOSE = 'game los'
 GAME_VICTORY = 'game victory'
 LEVEL = 'level'
 
+# 界面图片文件名
 MAIN_MENU_IMAGE = 'MainMenu'
 OPTION_ADVENTURE = 'Adventure'
 GAME_LOOSE_IMAGE = 'GameLoose'
@@ -102,10 +101,15 @@ BACKGROUND_TRIPLE = 8
 MAP_PLANT = 'plantnames'
 MAP_SLEEP = 'sleep' # 有没有休眠的蘑菇，作是否能种植咖啡豆的判断
 MAP_PLOT_TYPE = 'plotType'
+# 地图单元格区域类型
 MAP_GRASS = 'grass'
 MAP_WATER = 'water'
 MAP_TILE = 'tile'  # 指屋顶上的瓦片
-MAP_UNAVAILABLE = 'unavailable' # 指完全不能种植物的地方，包括无草皮的荒地、毁灭菇坑、冰车留下的冰
+MAP_UNAVAILABLE = 'unavailable' # 指完全不能种植物的地方，包括无草皮的荒地和坚果保龄球等红线右侧
+# 特殊的：冰车冰路（自动消除、辣椒消除）、毁灭菇坑（自动消除），由于这些只能在关卡中产生而不能初始化产生，所以只有区域类型没有初始状态
+MAP_FROZEN = 'frozen'
+MAP_HOLE = 'hole'
+# 地图单元格状态
 MAP_STATE_EMPTY = {MAP_PLANT:set(), MAP_SLEEP:False, MAP_PLOT_TYPE:MAP_GRASS}  # 由于同一格显然不可能种两个相同的植物，所以用集合
 MAP_STATE_WATER = {MAP_PLANT:set(), MAP_SLEEP:False, MAP_PLOT_TYPE:MAP_WATER}
 MAP_STATE_TILE = {MAP_PLANT:set(), MAP_SLEEP:False, MAP_PLOT_TYPE:MAP_TILE}
@@ -181,8 +185,9 @@ TORCHWOOD = 'TorchWood'
 # 植物生命值
 PLANT_HEALTH = 300
 WALLNUT_HEALTH = 4000
-WALLNUT_CRACKED1_HEALTH = 4000//3 * 2
-WALLNUT_CRACKED2_HEALTH = 4000//3
+WALLNUT_CRACKED1_HEALTH = WALLNUT_HEALTH//3 * 2
+WALLNUT_CRACKED2_HEALTH = WALLNUT_HEALTH//3
+# 坚果保龄球攻击伤害
 WALLNUT_BOWLING_DAMAGE = 550
 
 # 阳光生成属性
diff --git a/source/state/level.py b/source/state/level.py
index c96178c..1a0b87b 100644
--- a/source/state/level.py
+++ b/source/state/level.py
@@ -504,7 +504,7 @@ class Level(tool.State):
         elif self.plant_name == c.CHERRYBOMB:
             new_plant = plant.CherryBomb(x, y)
         elif self.plant_name == c.THREEPEASHOOTER:
-            new_plant = plant.ThreePeaShooter(x, y, self.bullet_groups, map_y)
+            new_plant = plant.ThreePeaShooter(x, y, self.bullet_groups, map_y, self.map.background_type)
         elif self.plant_name == c.REPEATERPEA:
             new_plant = plant.RepeaterPea(x, y, self.bullet_groups[map_y])
         elif self.plant_name == c.CHOMPER: