i have a technique for making motion blur that uses very little power and is simple to implement. the blur is generated using the "broken" subtract 0.0 shader. that shader seems to capture frames and slowly fade them away, so when u move an object under it, it captures all of its movement, and adjusting the opacity of the filter
That effect is called frame-feedback (previous frames fade out). You can do it properly with a canvas with grab layout and less than 100% opacity - using a "broken" shader relies on undefined graphics card behavior and might look borked for other people. Personally I find it quite an irritating effect, and it's definitely not a true motion blur, more of a stepped trail effect, like spawning fading-out sprites behind a moving object.