Here's some interesting tidbits for the pirate NES Hellraiser game
which was developed by the very well known Color Dreams but was
eventually canned:

Dan Lawton and Phil Mikkelson had wanted to make a Hellraiser game for
the NES. Phil had started the work with the Hellraiser game, by
obtaining the licensed and drawing the preliminary "screenshots" scene
in the old magazines.

"I contacted Clive Barker and got the ball rolling with the project.
Dan knew what Hellrasier was but I don't think the Chinese guys (Eddy
and his brother where the other owners of the company) really knew
what it was until we signed the deal. I made the screen shots that
were used in the Gamepro magazine article."

Dan had envisioned a Hellraiser game that was physically impossible to
design, by normal means that is. Dan developed the strangest concept
ever: design a special cart. Mr. Lawton had known a man named Ron
Risley. Giving Ron specifications for the cart, Dan watched as Ron
Risley constructed a "super cartridge."

According to Ron Risley, "My recollection is that the original NES
cartridge used two ROMs, one as a character generator and one with the
program code. What I did with the SuperCart was create a complete Z-80
computer with its own ROM and RAM, and then mapped a second access
stream into the Z-80 RAM for the NES console.

The Z-80 could then modify the character generator and the NES's
program code in real time. For some applications (especially
player's-eye view or "3-D" rendering) we would actually replace the
entire character generator during horizontal retrace, so that we had
pixel-by-pixel control of the screen -- something you couldn't do with
straight NES cartridges even if you had the processor power (which you
didn't). So the effect was that we greatly increased the effective
amount of available ROM, we improved graphics control, and we had a
complete Z-80 that could run as a graphics co-processor."

By the time the cartridge design was completed, Color Dreams decided
against the Hellraiser game. Some of the reasons are as follows:

# Dan was not totally satisfied with the color changing speed
# Carts would cost around $100, this would produce lower sales
# Their Hellraiser license was about to expire

A few things remain from the old Hellraiser game. Color Dreams began
to manufacture the labels for the game, I am fortunate enough to own a
few of these. There were also a few mockup pictures seen in adverts
and magazines. Phil Mikkelson once told me that these screens were
grabbed from an Amiga.

Roger Deforest was the graphics artist behind the PC version of
Hellraiser. He drew up a few enemy sprites and a title screen, all of
which he gratefully shared with my site. Below are a few words from
Roger himself.

"I did do some graphics for Hellraiser, which was never released. I
still have the graphics if you're interested in putting them on your
site. I don't think Color Dreams owns them. The title screen came out
kinda cool, but some of the monsters are just okay. It's mostly
nostalgic for me, and good for a laugh!

I worked on Hellraiser which you know never was released. They had the
rights to make the game for several years and just sat on it. I don't
know why. We were gonna use the Wolfenstein 3D engine for the game. I
remember that the progammer on Hellraiser got the graphics in and the
monsters working. It was all very bare bones stuff, but it was getting
there and looked like it'd be fun. And then it was abandoned again for
other titles."

The following was grabbed from an old brochure included with some
copies of King Neptune's Adventures. "Super-16 cartridge delivers 16
bit performance that plugs right into your 8 bit Nintendo System.

Hellraiser is the first game to use our advanced technology that
pushes the NES further than ever before.

Experience the pleasure of 16-bit performance. Experience the pain of
Clive Barker's Hellraiser.

Can you locate the strange cubes that open doorways to the darkrealm?
Can you solve the puzzle of the Lament Configuration? Pinhead,
Cenobites, and all of Hell know the answer. From the darkness far away
laughter echoes."

http://www.planetnintendo.com/thewarpzone/cdreams5.html