
The improvements:
Overall smoother and clearer presentation.
There's some primitive sprite angle changing occuring- I think it needs to be based on relative position though, not angle?
The foreground (including the player sprite) no longer gets reflected in the lensing effect (always did).
The new lensing technique can now allow the Spectre to go behind other objects.
It is compatible with all texture filtering and upscaling options but not multisampling.
The Faults:
The purple sprite should only be enabled for the closest Spectre but is visible for those not being counteracted by the shader.
The lensing only works on the most recently seen Spectre.
No movement interpolation.
The death sequence (now animates) but gets squashed by the bounding box.
The perspective is only being approximated by the shader by scaling to it's maximum area.