Definitely not as refined as the original, but a novel idea anyway.
one thing that I could not get used to while playing: the plants in the pipes just come up at regular intervals, whether you're there or not.
afaik there is no gamepad support either.
screenshots: http://72.14.207.104/search?q=cache:joyCRVj53W0J:miamibeachpersonaltrainer.com/destructoidmirror/nes-super-mario-brothers-playable-in-3d.htm+mario+2.5d&hl=en&gl=us&ct=clnk&cd=4&client=firefox-a
download: http://www.megaupload.com/?d=6X0IDQYC