i made a game called phase you can play it here

http://dl.dropbox.com/u/3923260/phase.html

i made a version you can mod Creative Commons Attribution Non-Commercial license

http://dl.dropbox.com/u/3923260/phase.zip

it has a couple more tiles and different rules for portals that i feel make the game more interesting

game maps are in map.png

colors are as follows

blue - obstacle
purple - can walk over, can't portal
green - flag
red - kills
dark cyan - portals won't transfer this, can walk over
cyan-blue - portals won't transfer this, obstacle