First of all I should point out that this is quite possibly the least accessible game I have ever played. I can't whole heartedly recommend this straight to either a point and click adventure fan or a Suda 51 fan, as Flower, Sun and Rain's gameplay won't please either camp.
Flower, Sun and Rain is (as the product description states) essentially a point and click adventure game except the each puzzle is solved by using numbers and there is only one item - a guide book. Most times a story puzzle occurs the protagonist (Sumio Mondo) 'jacks' into an item or person to enter a code that can be anywhere from 1 to 10 digits long in order to progress. Most puzzles are answered by on screen events, hidden in the 49 page guide book, character dialogue or some fairly advanced mathematics, which sounds relatively straightforward but requires an awful lot of lateral thinking. The difficulty curve is steep initially but progresses at a reasonable level, as the player gets into the right frame of mind. There is also a great deal of repetition and backtracking in some sequences, which many will find off putting.
An early issue with the game is getting into that frame of mind. The clues can sometimes be confusing and have lost something in the switch of culture. For example, an early lost and found puzzle (required for bonus content) requires you to find the combined age of two statues that have "just entered adulthood". Instinctively, I assumed they were each 18, making the answer 36, but was incorrect. I then took the American 21 age, but was again incorrect. Instead, the answer is 40, as in Japan 20 is the age of adulthood, but assuming no prior knowledge few will know this.
The main problem with the game is simple, the graphics vary from scene to scene, but are largely poor. FSR was originally a Japanese only PS2 and boy can you tell this is a port. Flickering images and scan lines dog the often ugly environments which is a pity, as director Suda 51 has obviously worked hard to create a distinct style in the character animation, it's the basic features that make this fall short.
If you can look past this however, there is a remarkable story beneath. Initially events lack any connection, with a stream of surprisingly intriguing characters asking for your help. There is an obvious Kafka influence as well as the usual breaking down of the fourth wall and dark social commentary associated with Suda 51 games. The story is wonderfully surreal without the ridiculous nature of No More Heroes and writing brilliantly sharp despite not originally being in english. A real treat to combat most drab, poorly constructed stories in most modern video games.
Another positive is the sound of the game. The music is very well orchestrated which helps create a strong atmosphere which almost compensates for the terrible graphics (but not quite), as are the sound effects, but the sound made when a character talks does begin to grate as you progress thorough the game.
Most of the criticism labeled at the game is fair enough, but I feel I have to defend allegations of a racist undercurrent in story. There is a scene in which a black character requests an afro wig and is given an old mop head and a character refers to you as 'master', which one reviewer has interpreted as racist. The first instance isn't intended as a racial slur, the entire chapter deals with the vanity of celebrity and the character in question is unable to act himself without a mask of some sort, usually it is a wig but a mop will do the same. The 'master' references are a little more difficult to explain without spoiling the story, but essentially Sumio is called master as he is the only one who can stop the endless daily cycles and all the staff are aware of this (regardless of race). It's also worth noting that Suda 51 is one of the only people in the gaming industry who creates characters from racial minorities that don't conform to stereotypes (look at Garcian Smith from Killer 7).
Overall, the game has some obvious flaws and demands an awful lot from it's players, but if you're prepared to put in the effort and not be put off by the visuals, there is an awful lot to admire.