Once is a small, perfectly formed film about some very big themes. Most obviously, it is about the power of music to connect - after all, it is a film about an Irish busker meeting a Czech immigrant in Dublin, and them making (very beautiful) music together. But it is also about the possibility of a brief, intense connection reverberating throughout one's life, something that is probably true for many people, but rarely depicted well in films - perhaps only the Before Sunrise / Before Sunset diptych do it properly.
Musicians Glen Hansard and Marketa Irglova play the unnamed Guy and the Girl respectively, and their relationship, shot through a long lens, feels appropriately real rather than the stuff of film: lots of faltering words, awkward pauses, and missteps. There's no meet cute. No fireworks. Just the natural progression of two people coming together, trying to figure out the boundaries of their relationship, falling slowly.
And natural is the right word. Once is probably the least forced "musical" (if you can call it that), and one of the least forced films around. The songs come in precisely at points that musicians should be singing, rather than any unnatural burst into song; the long tracking shots are a nice, realistic counterpoint to the staccato cuts of rom-coms; and Dublin itself is presented in all its dear, dirty glory - while there's clearly the more upscale pedestrianised shopping areas of the Celtic Tiger's capital, it's also a city of bedsits and migrants crowding around to share TVs.
And the bittersweet ending (which, in a way, is the opposite of the famous ending to The Graduate) is a just-right moment of perfect joy and sadness mixed into one. It lingers, just like the relationship continues to reverberate for the Guy and the Girl, just like the Hansard/Irglova songs stay emblazoned into the mind. You fall slowly for Once, but by the time you get to its end, it has taken your heart.