I assume the blocks are "kinematicbody".
I think you added scripts to them.
erase
moveandslide
or
moveandcollide
//////////////////////////////////// change //////////
Make the blocks "Staticbody".
add group == group name = blocks
and let the "bullet" signal them
now bullet = Kinemetickbody2d
change
bullet = Area2D
and get "Bullet" Area2d.
example :
bullet scene (area2d)
if body.is_in_group("blocks"):
body.explode()
//// Blocks scene
func explode():
queue_free()
///////// Or
don't adding code to blocks
just add group
Bullet scene
if body.is_in_group("blocks"):
body.queue_free()