Bullet rain is denser and its bullets are no longer stopped by anything

Interval dropped from 1.0s +- 0.6 to 0.4s +- 0.25 (about 2.5 bullets per second instead of 1), which measured 13 drops in 6 seconds versus 6 before. bullet.gd gained stop_on_obstacle (default false): the probe raycast is disabled, so rain bullets fall straight through terrain and ropes and are only recycled by their lifetime or by dropping past despawn_y. Verified a bullet falling from y=190 goes through the floor at y=225 and despawns at y=340. Also picks up the editor changes: the rope tiles were removed from level 3 and a few nodes gained unique ids.

scripts/bullet_rain.gd

@@ -1,20 +1,19 @@
 extends Node2D
 
-## 子弹雨：从天上随机横坐标往下落子弹，密度可以调得很疏。
+## 子弹雨：从天上随机横坐标往下落子弹，密度可以调。
 ##
-## 落下来的子弹撞到地形、或撞到你铺的「绳子/木板桥」就会消失 ——
-## 绳子的碰撞放在 TileSet 的第 2 物理层，只有子弹的探针（mask = 3）会检测它，
-## 玩家（mask = 1）和钥匙（跟着玩家的 mask）都不受影响，能直接穿过去。
+## 落下来的子弹**不会被任何东西挡住**（bullet 的 stop_on_obstacle 默认关掉），
+## 会一直穿到关卡底下才回收。
 
 const BULLET := preload("res://scenes/prefabs/enemies/bullet.tscn")
 
 @export var enabled: bool = true
 ## 平均多少秒落一颗（数值越大越稀疏）
-@export var interval: float = 1.0
+@export var interval: float = 0.4
 ## 间隔随机浮动范围（0 = 完全固定节奏）
-@export var interval_jitter: float = 0.6
+@export var interval_jitter: float = 0.25
 ## 开场后第一次落下的延迟
-@export var start_delay: float = 1.5
+@export var start_delay: float = 1.0
 ## 生成高度（相对自己的 y，负数 = 从屏幕上方外面）
 @export var spawn_y: float = -30.0
 ## 水平撒落范围：以自己的 x 为中心，左右各一半
@@ -56,6 +55,7 @@ func drop() -> void:
 	bullet.bullet_color = bullet_color
 	bullet.speed = fall_speed
 	bullet.damage = damage
+	bullet.stop_on_obstacle = false
 	get_parent().add_child(bullet)
 	bullet.global_position = Vector2(
 			global_position.x + _rng.randf_range(-span * 0.5, span * 0.5),