Rain is beautifully simple. There is a boy who is more or less the player. There is a world that is achingly sad. There is a girl who is purely good simply by being the game's lone solace in companionship. There is also an unknown figure relentlessly trying to separate the other two characters, making it just as evil as the girl is good. The efficiency of the concept is almost scientific. How surprising it is that the design somehow manages to muddle such a clear idea.
When the player starts controlling the boy, they are stuck in a city of rain and night. Chalk scribblings on walls indicate that there might still be other children. Perhaps they are gone. The streets are disheveled and empty but all seem to be cruelly named “Chocolate” or “Candy.” The game does offer the context of the girl to be found but, much like in Playdead's Limbo, the environment creates an inherent need to find companionship.
The rain itself plays an important part in the relationship between the two children. Upon stepping into the city, everybody loses their identity. They exist in that they have mass and their actions have impact on the world, but they are invisible and they have no voice. It's the pouring rain that gives them their silhouettes and allows them to communicate with others. The rain is the common ground for all the characters.
The third character, the unknown figure, is what haunts them more than the dreariness. Early chapters before the boy and girl meet up have a tangible immediacy as the player is compelled forward to find a companion while also pushed ahead as the unknown figure chases them down. However, it's when the pair unite (not so far into the game) that the biggest question is asked: What now? They can't keep running forever.
As wonderful as this all is in concept, the design ends up being a letdown. The game almost constantly rips the control away from the player and shifts the camera to show mundane events (the unknown figure popping out, puzzle setups, etc.). This type of design can ruin the flow of a normal game but it's even worse in Rain as the boy may be invisible when the camera moves and suddenly the player has to reorient their avatar with no visual cues. It's incredibly jarring to have to flail the joystick around until the boy runs into the rain or a puddle before continuing on.
Rain has moments of terror as monsters chase the protagonists relentlessly. It can be incredibly cold in the city's empty, wet streets and it provides brief but welcome warmth through the character interactions. Everything hinges on simply being in this world but the design too often rips you out of it. The concept is elegant but the execution is sloppy. Rain feels like a game that was thought about a lot but played very little.