The program was originally for Windows-only, but after a donation drive in early 2007, it was ported to Mac OS X.

[4] In a letter dated 26 March 2007, Activision requested that Piegdon "immediately cease any and all use of the "Piano Hero" name in connection with the distribution and promotion of [his] video game and agree not to use such in the future".

A "Learning Pack" key could be purchased to unlock the freemium additional features, such as a sheet music display mode.

Synthesia will rate the player's performance afterwards and give a score which can be submitted to an online scoreboard.

Synthesia also has a paid "Learning Pack" that allows users to view music in musical notation, as well as multiple practice features, such as "Melody Practice" which pauses the piece whenever the user misses a note and only continues when the right note is played.