All of the assets required can be downloaded here.
The sprites for the boxes are in the Traps --> Saws
The Chain group is just many duplicates of Sprite2D using Chain.png as the texture (found in the Saw folder)
Create any level you like.
You may copy my level layout.
Note that you don't have the saws yet
NOTE: You need to set the TileMapLayer node Z-Index to 1
So that the saws appear behind the platforms
Create a new scene for the Saw
Use an Area2D as the root node
Add an AnimatedSprite2D as a child of Area2D
Add a CollisionShape2D as a child of Area2D
Select the AnimatedSprite2D node
In the Sprite Frames property
Rename the default animation to off
Use the off frame of the Saw
Add a new animation name it on
To add frames from a sprite sheet
Set Horizontal frames to 8
Select the CollisionShape2D node which is a child of Saw
This should fit the Saw exactly
Attach a new script to the Saw node
Connect the body entered signal
Code the body entered function
To check if the body is the player
and if so call the player hurt function
Add an AnimationPlayer node
Rename it to LargePlatformAnimation
Click on Animation to add a new one
Click Create to add the track and RESET track
With the timeline at 0 seconds
Select the saw on the larger platform
Find the Position property
Hit the key to make a keyframe
Move the Saw to the top right corner
and repeat this for all corners
for each saw in the level
by adding and AnimationPlayer node
for each saw in the level