Mr Dremel to the rescue! Last year I used clay carving tools to carve out and do different depths in the pumpkin hide. While it wasn't too bad, I wanted to try my trusty old dremel with the small router attachment.
Step 1: Source Material/Tools
So I went on the net and found an image of Mega Man that I liked, and could easily cut out the head in photoshop. Turned black and white, then printed.
Step 2: Trace Template
I think took the modeling pin tool (you could use any pin or probably even a toothpick) and poked holes around all the lines on the template. I left space for line thickness too. The reason I did this over free handing it, is because I am lazy, and not that good at free handing on a pumpkin.
Step 3: Trace the Pin Wholes
If you are going to freehand I would use a ball point pen that has a watery ink in it (don't know how to better explain it). It draws really easy on the pumpkin, and wipes off easy too. That way you can sketch on the pumpkin, then use a sharpie once you have what you want, then clean up the pen marks with a wet paper towel.
Step 4: Cut the Lines Out
Step 5: Time to Dremel
The deeper you go the more light that will shine through. I am not sure which is better... I think starting shallow, then slowly working deeper into the hide is the best. The most important thing to do is to check your depth. Make a test mark, then shine a flash light down the hole, it should give you an idea of how much is left. Also, you can always use the clay tools to carve out some of the hide from the inside (did this with the other pumpkin).
I started at the top, and worked my way down. In area's that are large where you won't be able to support the router attachment, just keep the edge facing you flush against the pumpkin... its not an exact science, so that should be good enough.
Step 6: Mistakes
I walked away for a bit, then came back to try and fix it. You can usually fix these types of mistakes with toothpicks stuck into a more solid piece. So here you can see the two toothpicks sticking into the part with more meat, and then into the eye.
We will just say that I did that on purpose for these instructions.
Step 7: Clean Up
After my repairs, and finishing off all the work, this is what I ended up with. I am very pleased with the results, even with the mistake.
Here are a couple other pumpkins as well... yes I am a video game geek.