This was a lot of fun and very innovative! The physics and controls just felt perfect, and the variety in levels and enemies kept things fun the whole way through. The shadows/line-of-sight graphics looks really slick, I'd love to hear how that's done. I think if there were more dungeons (for longer gameplay), and of course some graphics, this would make for a good commercial game.
Drawing shadows that way is actually really easy. You take a wall line and project it away from the player by a small amount (half a tile here), then project it very far away (like 100 tiles or something silly, way off screen). Take the four points you get from that and draw that trapezoid shape. Repeat for every wall.