Downstream Panic! is a colourful puzzle game that mixes elements from LocoRoco with Worms.
A massive cyclone has sucked all of the fish out of the oceans! The player must safely guide them back. Levels start at the top of the area where the fish are contained in a blob of water. They need to reach the ocean safely at the bottom of the screen with guidance of the player.
Using a variety of creative tools like fans, onions, rockets, and cloud factories, the fish can be guided through platforms, past hungry sharks, piranhas and many other dangers. The tools can also be used to control the flow of the water and the direction the fish travel. Plants will stop the flow and by blowing flowers bridges are opened. At the start of the level, the area usually needs to be scanned first using the free camera perspective to discover all the hazards. Certain fish can be sacrificed, but a sufficient number of them needs to reach the ocean.
The regular mode eventually unlocks the Free Play and Survival modes. In Free Play the player can spend the money from regular games to buy tools for the stages. In survival all levels are replayed in succession, but lost fish are not regained in the next level.