RockFree is Acclaim's entry into the popular rhythm game genre. It is a browser-based 2D game that lets you create a rocker and play along to match the notes Guitar Hero style on a selection of tracks. Control is via keyboard, with full gamepad support planned.

Cover versions of popular songs from several decades are available, with a player able to have three tracks in his or her library at any given time. To get more library songs, users can select from over 40 free options or buy more storage space or new tracks with micropayments.

In addition to solo mode, players can compete against others for dominance in rock battles of up to eight. In game points are earned for character upgrades. Another standout feature is RockFree's upload system, which lets players upload their own tracks to play along with; even letting others try them out. RockFree is currently in open beta and looking toward a full release later in 2009.