This particular perler bead Pokemon is amazing. I love how you used varying shades available to you to re-create the in-game image of Arbok from the Diamond and Pearl versions.
For technique, I gave 5/5. I feel that the use of perler beads to create such an intricate image is fascinating to me. For impact, I gave a 4.5/5 because while this image is neat, I doubt many other people would follow your lead.
And as for originality, I sadly gave 4/5. But it's fan art, so I don't think it would matter anyway.
To conclude this critique, I would like to say that these kinds of designs are awesome, and I hope you continue to do more of them in the future.
I love how these look, I love the feel and look of the beads and the colors you've chosen to make these pokemon, and I love how happy and very "clean" they look!! You could make thousands of these and I'd never be tired of looking at them and wanting to collect them all.