Make me a game idea: here is one, worked out

Today's idea: Last Train Home

You are the last passenger on a night train. At every stop, someone gets on. Some are normal. Some are not. You have one job: pull the emergency brake before the wrong one sits next to you.

The twist is that you never fight. You watch, compare and decide. Each stop gives you a few seconds to spot what is off: wet shoes on a dry night, a face that was on the platform two stops ago. Pull the brake too early and you are thrown off the train. Too late and the lights go out.

Why it works: one action, a clear risk, and a short round. It is easy to explain, hard to master, and friends can play it side by side, arguing about who looked strange.

• Type this into Roam. "night train horror, at each stop someone boards, spot the one who is wrong and pull the brake, 10 stops to get home."

Not it? Roll again

• Lost and Found. Run a lost and found desk where every item has an owner who lies. Type: "lost and found desk, match items to owners, some owners lie, 5 days."
• Elevator Pitch. Your elevator stops on random floors and each floor is a tiny game. Type: "elevator stops on random floors, each floor is a 20 second mini-game, reach the top."
• Bad Weather. You control the weather and must ruin a picnic without getting noticed. Type: "control the weather, ruin 5 picnics, people get suspicious if it changes too fast."
• Dog Walker. Walk six dogs on one hand. Each pulls a different way. Type: "walk 6 dogs through the city, each pulls toward something, get home with all of them."
• Last Slice. Four friends, one pizza slice, a table full of distractions. Type: "four friends at a table, grab the last slice when nobody is looking, multiplayer."

How to tell if an idea is for you

Say it out loud to a friend in one sentence. If they ask a question about how it plays, it has a hook. If they nod and change the subject, roll again. The real test is playing it, which takes one sentence on Roam, a free iPhone app that builds the game, art and rules for you.

Questions people ask

Can you give me a random game idea?

Yes. Today's is Last Train Home: spot the passenger who is wrong and pull the brake in time. Five more ideas sit just below it.

What makes a game idea good?

One clear action, a risk, and a twist on something familiar. If you can say it in one sentence, it is ready to test.

What do I do once I pick an idea?

Make a small playable version. On Roam you type the sentence and play it on your iPhone, then change it by talking.