There exists a playable demo of Eternal Sonata, available for both the Xbox 360 and PlayStation 3 versions of the game.
The demo may be downloaded via either the Xbox Live feature for Xbox 360 players and via the PlayStation Network for those using PlayStation 3. Both options require having an account with the respective services, though the demo itself is free.
The demo curiously does not follow the actual story of Eternal Sonata and does not present any story cutscenes. It begins the player with the playable characters of Allegretto, Beat and Polka starting at the Path to Tenuto. The team must then travel through the path, defeating monsters along the way and eventually reaches Tenuto Village. The monster Great Coconut may be encountered in darkness, though in the final version of Eternal Sonata, the Very Very Empty does not morph into Great Coconut in darkness until the Agogo Forest area. The characters begin at Level 1 with 0 EXP. Beat has access to the Night Shot ability for Photos, though in the final version, he does not learn this until Level 12 in both versions.
In Tenuto Village, the NPCs behave as they normally would if Allegretto was visiting the village in Chapter 2. Notably, Allegretto can find a Score Piece in one of the houses in the village and can play it with Gentlemanly Pop, who has been moved to the village, though it gives a Rank F. In the final version there are no Score Pieces found within Tenuto Village and Gentlemanly Pop is found within Forte City. Solfege also present in her and Polka's house and talks with Allegretto as she would if the player were revisiting the area in an Encore Mode playthrough in Chapter 7.
The party continues to Heaven's Mirror Forest, where there is at least one other NPC who in the final version is not present. They eventually reach and defeat Forest Boar. Following this, a screen is presented with info on how and when to get the full game. A set of cutscenes from the game is then presented.