Use onready feature on Game script

Game.gd

@@ -1,15 +1,13 @@
 extends Node2D
 
-var cam
-var p1
-var p2
+onready var cam = $Grid/Camera1
+onready var p1 = $Grid/Player1
+onready var p2 = $Grid/Player2
 var dist_max = 900
 var zoom_rate = 0.001
 
 func _ready():
-	cam = $Grid/Camera1
-	p1 = $Grid/Player1
-	p2 = $Grid/Player2
+	pass
 
 func _process(d):
 	cam.position = 0.5 * (p1.position + p2.position)