Hi Terry! I'm afraid that if the overlay is an extra asset (like a transparent png, or something) that'd go against the rules of the jam. This is not the first time someone as tried to do a CRT effect for their game, though. And there's two ways to go around it:
- Use a shader (if your engine of choice is capable of using one), or
- bake the CRT effect in the background & sprite/CG.