Game Design Challenge: Sidekick

I've decided I will post my past submissions to the Game Design Challenge, while I finish writing and editing the stuff I have pending.
My first submission, according to my mail search engine, was for 2009's November challenge, in which participants were asked to create a sidekick to breath new life into an old franchise.

My idea was based on Doom, and offered the possibility to play with Pinky as a demon companion. I'd love to have the chance to, sometime, create this as a mod for DooM 3. Or see someone else do it.
It got an honorable mention when the results were published (yeah!), and the Game Career Guide staff was nice enough to add a picture of Pinky to my submission. I must admit I didn't consider that people not too familiar with the Doom universe would have no idea who Pinky is.
Lesson learnt: adding some art can clarify things you did not know need clarification.

Series: DOOM
Sidekick name: Mr. Pinky

"You killed its brothers, destroyed its master and melted its home. Thrice. This time, it wants to share the fun."

In Hell, waiting for the next Earth invasion, demons are dead bored. Craving for some more fun and a chance of survival when The Marine comes, one of them has decided to change sides in the coming war.

Once again, fight the hordes of Hell with your trusty BFG and chainsaw, but feel lonely no more. You can count on Mr. Pinky, bonded to you by the Soul Chain, to follow you anywhere you go.

Mr. Pinky's abilities:

• Growl when there are foes nearby.
• Detect secret areas.
• Grab enemies at your command, keeping them still for that deadly shot.
• Life re-generation.
• 10 seconds re-spawning.

You two will never be able to part ways further than the Soul Chain allows, including while Mr. Pinky is dead, when, unable to drag it, you'll resist until it re-spawns.

Through the power granted by the Soul Chain, when overwhelmed by the pain, your corpse will drop to the floor and your soul will travel to Mr. Pinky, giving you control over it while its re-spawning powers are channelled to you. Slaughter demons between your fangs, charge with demonic legs or thrust your claws inside your enemies corrupted flesh; smell close-by enemies or secret areas in the form of coloured fog.
Mr. Pinky's speed will be halved while dragging your body around. Should Mr. Pinky die, re-spawn in ten seconds and hit your relaxed enemies like they want it. Marine's re-spawning will continue once Mr. Pinky is back on its feet.

Novelties available:

• Co-operative play with you and your friend each with your pet or as a Marine and Mr. Pinky deadly tandem. Option available in all other multiplayer modes.
• Berserk allows you to drag Mr. Pinky's corpse at half speed, and it will be able to drag yours without penalty.
• With special weapons, use Mr. Pinky as ammunition, or throw your sorrowful remains to the enemies.
• Share Mr. Pinky's abilities, speed and strength with the Soul Mate item.
• Once you finish the game, return as a lonely Mr. Pinky in history or on-line mode.

Difficulty modes:

1. I love kittens- Benefit from re-generation. Marine's re-spawn time is not reset when Mr. Pinky dies. No friendly fire.
2. Taking the demon out for a walk- Re-generation rate is halved for both while both are hurt. Once your or its life is full, re-generation works at normal speed.
3. Share the love- Re-generation only works in one of you at a time, with Mr. Pinky taking priority. Re-spawn time resets when Mr. Pinky dies.
4. We have demons for breakfast- You will not benefit from Mr. Pinky's re-generation, but will still re-spawn.
5. We are a demon's worst nightmare- Pinky's re-generation rate is halved while you are alive. Re-spawn time is doubled while you or Mr. Pinky are alive.

 Edit: I forgot to thank Frontier Studios' Dog's Life and 2K's BioShock for some of the ideas.