Part 1:
http://dev.opera.com/articles/view/creating-pseudo-3d-games-with-html-5-can-1/
Part 2: http://dev.opera.com/articles/view/3d-games-with-canvas-and-raycasting-part-2/
Demo: http://devfiles.myopera.com/articles/650/step_4_enemies.htm
Part 2: http://dev.opera.com/articles/view/3d-games-with-canvas-and-raycasting-part-2/
Demo: http://devfiles.myopera.com/articles/650/step_4_enemies.htm