What would it feel like to shunt the moon around in the sky? Or rather, how should it feel? This is one of those weird, tantalising sorts of questions game designers have to deal with on a daily basis. Designers like Sergey Mohov in fact, who's part of the team making Lune - a game that's about, y'know, shunting the moon around in the sky.
"The moon is a heavy, heavy object," says Mohov. "It's a celestial body. It feels heavy when you move it. The sound you hear when you move the moon is a deep rumble, and it's accompanied by the ground trembling. The ground, along with all the objects that are on the surface." Yes: that should do it.
Mohov's making Lune with a small group of fellow students at ENJMIN. (ENJMIN's the École Nationales du Jeu et des Médias Interactifs Numériques, a video game graduate school based in southwestern France. It's also proof positive that nobody beats the French when it comes to the poetry of naming institutions.) "The important thing about ENJMIN is that it's all about projects," Mohov enthuses. "We practice a lot, form teams and spend most of the time actually making games, hands on. The school lets you keep all the rights to your projects and encourages any continuation the projects might have. You also get valuable advice, but aren't controlled. This makes for a really good creative atmosphere where people tend to do interesting things."
Mohov and his friends are describing Lune as a game about reflection and solitude. It's already got a lovely, lonely sort of atmosphere, and it promises to unfold with a sense of controlled spectacle as you explore a mysterious island set in the middle of a dark ocean. "The idea was to make something personal to all six of us, something that would keep everyone motivated and dedicated," explains Mohov. "We formed a team first, then spent almost two months brainstorming and throwing ideas around.
"Everyone on the team came up with a theme, kind of like Ludum Dare themes: just a couple of words," he continues. "Then the team together thought of a game concept for each of the themes, making it six completely separate game ideas, some of which we then ended up using in Lune. One of the themes was Moon, basically, and it made all of us want to make a game about controlling it. When we talked about the idea to our peers, they were all very positive on the fact that controlling the moon would be awesome. The moon tends to mean different things to different people, but controlling the moon is something that invariably inspires awe in everybody."
Lune's still taking shape but it seems to be a gentle puzzler built of tiny, glittering victories and tailored to reward experimentation. "There are three types of things that you can do with the moon," says Mohov. (Hopefully he's still talking about the game at this point.) "You can modify gravity, you can control the tides and you can change the way the moon reflects light." Fairly straightforward puzzle components, perhaps, but these planetary matters should provide an elegant counterpoint to the small-scale business of your own on-foot exploration. There's something strikingly perverse about using a massive lump of orbiting rock to open a little wooden door, and this sense of disparate objects that have become entangled over ludicrous distances gives Lune a delicacy and a poignancy which marks it out from other physics games.
"Most of the times you will be trying to combine these tide, gravity and light tricks in order to achieve goals that you set for yourself," says Mohov. "You will inevitably want to climb higher in the tower that occupies most of the island where the game takes place, but most of the time you will spend exploring different levels of this tower, moving objects around, climbing on top of them, avoiding the island's Guardians and observing the effect your actions have on the environment."
The team's still at work on the controls, but for the moment you'll manipulate the moon using the WASD keys: W and A to pull it closer or push it further away, and S and D to roll it along its orbit. In the simple prototype that's currently available, both of these actions affect the tide and gravity, lowering and raising the water level beneath a rickety little bridge and sending shimmering pebbles dancing in the air. There's a wonderful sense of weight to the whole thing, partly due to the grating of the audio, and partly because the moon is a little sluggish to start moving and equally sluggish to stop. Leave it be, and it gets back to tracing its normal orbit, too - and that helps conveys a sense that you're meddling with something of real heft and consequence.
Then there's the art: the spindly, strangely stoical form of the female protagonist set against the deep dark blues and greys of the island. Put that together with the roll and mutter of waves and the creaking of old wood and you start to gain a real feel for this desolate, mysterious place. What's its story? What's your story? Good questions - and with a playable vertical slice due in June, there's still so much to be fleshed out by the team back at ENJMIN.
"We really want to make the player curious," concludes Mohov. "The whole game is based on the assumption that the player will want to play with the moon, move it around, see how different objects react to the changes in gravity, see if they float when we bring in the tide, see how they reflect and accumulate light. It's all about exploring the environment and the effects your actions have on it.
"We're investing a lot of time into level design, in other words. We're making the world interesting as well as beautiful."