GDC's "alt.ctrl" section is a lawless land unified only by a single question: "why not?" It's living proof that anything can be a game controller if you just believe hard enough. And while many of the games on display can be gimmicky, Objects in Space feels like a game I'd play even without all the extra hardware.
It's about piloting a spaceship, except the ship is more like a submarine than a space-boat, space-plane, or space-automobile. You travel between systems, taking jobs and keeping your systems as quiet as possible to avoid radar detection. You have tons of control over the systems powering your space sub, but that means you've got to pay close attention and make sure everything's in working order.
It's really cool! I've never played anything quite like it. Here's a video (sorry about the quality; I recorded it on my phone):
Combat is tense as hell despite being visually minimal. It's nerve-wracking waiting for torpedoes to spin up while an enemy's salvo sails rapidly in your direction. And goodness, the feeling of finally being able to flip the switch and press the big red button to fire your own is just fantastic.
The controller adds a ton on the immersion front, but the game's fully playable without it. That said, using a real key with poofy stuffed dice attached to start my virtual space submarine is a highlight of my GDC so far.
Here are some more pics of the control setup: