I made this glow mechanic after being inspired while installing Windows Longhorn, and it just kept improving.
Let me know what you think!
You can change the scale of the glow for different sizes, or make it actively change for a flicker.
You can change the transparency of the canvas for a brighter room.
You can make the glow follow any actor. (multiple glows will cause issues when they cross though)
You can also replace Data/Glow3.PNG with your own gradient for a different effect.
This is why I call it versatile!