Designing a game you can't see
In most games darkness is an obstacle. In Sonar it's the whole game, and getting that right took a couple of wrong turns.
Sonar starts on a black screen and mostly stays that way. You're a small submarine in a flooded cave with no light. Press ping and a ring spreads out from you, lighting up walls, pearls, the exit and whatever else is down there, for a moment, before it all fades again.
Seeing has to cost something
If pinging were free you'd just hold the button, the cave would stay lit, and it would be an ordinary swimming game. So every ping wakes up the creatures near you, and they come towards where the sound came from. Each ping is a trade: you need to see, but seeing tells something unpleasant where you are. Nobody needs this explained. They ping three times in a panic, get swarmed, and understand.
The ring tells you distance
The pulse spreads at a fixed speed instead of lighting everything at once. Nearby walls show up straight away, far ones a moment later. Ping into open water and nothing comes back for an uncomfortably long time, which is how you find out a room is big.
You steer from memory
Because everything fades, you're really navigating by what you remember of a room you saw a second ago. Our best tip: keep moving after you ping. The creatures head for where you were, so if you drift on, they arrive at empty water. Good runs have a steady rhythm of pings. Bad runs go silence, silence, then four pings in one second.
Your air runs down the whole time. Pearls give a little back and the exit refills it, so collecting and surviving usually point the same way, until the last pearl is somewhere you'd rather not go. Your hull takes three hits from a creature. Bumping into rock doesn't damage you, but it wastes air and makes noise.
What we got wrong first
The first version had a faint glow so you were never completely blind. It seemed kind. It also meant you didn't really need to ping to get around. Removing it made the game.
We also started with a very short ping cooldown, because waiting felt annoying in quick tests. But that made panic-pinging work, and panic-pinging is exactly what the game is meant to punish. A longer cooldown made it harder and a lot better.
→ Play Sonar · → The one number that made our survival game work