Levels 1&2:
Fake but very efficient lighting system, works just by using a black overlay (with Subtract blending) and the light sprites added on top (with multiply blending) then inverting the colors of the game

Level 3:
Based on my code from this game:
https://flowlab.io/game/play/2042191
The lighting code is simplified, with the "line-of-sight" completely removed, and the math optimized further into 1 Expression.