The age-old question of what the limit is in terms of ways Doom can be ported is still being tested, as one fan has taken it upon themselves to make the iconic FPS playable on a keyring-sized gaming system. With id Software said to be working on a new project, many will be speculating whether the studio will be once again bringing the world more exploits of the Doom Slayer. Perhaps the developer is looking to bring back Quake or maybe work on something different. However, there's no way of knowing just yet.