flOw is a PlayStation Network game, originally an online flash project by Jenova Chen and Nicholas Clark as a part of Chen's thesis research, but later adapted to a commercial game by thatgamecompany, which Chen co-founded.
The player controls a small, worm-like micro-organism on a bright, two-dimensional plane. On the PS3, it can be moved around by tilting the SIXAXIS controller in the direction the creature should swim. The PSP version is controlled with the analogue stick. There are six, gradually unlocked creatures to choose from (Snake, Jelly, Manta, Rogue, Hunter, Credit Creature), each with their own abilities such as poison, a swirling move to draw in plankton or a homing attack. The aim of the game is to eat other micro-organisms and evolve, moving deeper into the sea until the bottom is reached, leading the game to restart with a new creature. Evolving will change the creature's shape or grants new abilities. There are different power-ups, making the creature move faster or giving it a larger mouth. Certain larger enemies are made up of dots that need to be eaten to have it destroyed, requiring different strategies to take them out.
With each new level, moving deeper into the sea, the background, colours, enemies and music change. The creature is able to return to previous levels, or dive deeper, indicated by different icons. The game has straightforward controls and offers multiplayer sessions for up to 4 players, all using the same creature.
flOw applies the concept of dynamic difficulty adjustment. Players can choose to ignore large and dangerous enemies or come back to fight them later, striking a balance between the game's challenges and the individual abilities.