Wehey I love it!!!!
I dont think the darkness really added much to it, but nice idea on making gish a light source.
I love the way the heavy blocks carry you down to the lava and the little floaty block you ride down the lava on.
The weird ending was also quite cool.
oli
P.S. How do you make light sources, I know its object 8, but they always come out as anchor points for me.