Echo Deep

Swim a small submarine through dark underwater caves. You can't see the walls. Click to send a sonar ping and the walls light up for a moment. But be careful: fish hear every ping and swim to you. Collect pearls, stay away from fish and find the exit. Throw noisy buoys so the fish go to them, not to you. 12 levels, currents, jellyfish and upgrades for your submarine.

Move the mouse to steer. Click or press Space to send a ping. The ping shows the walls, pearls and fish. Right click or press E to throw a buoy. You can also move with WASD or the arrow keys. On a phone: drag to move, tap to ping. Collect enough pearls, then swim to the exit. Fish hear pings and fast moves. Near fish, move slowly.