What is the hardest challenge medal level in Guitar Hero 5?

Diamond is the hardest challenge-medal level in Guitar Hero 5.

Guitar Hero 5 introduced Career Challenges that could be tied to particular songs or opened up for players to choose a suitable song. Each challenge had three completion levels: Gold, Platinum, and Diamond. Diamond was the top tier and therefore the most difficult target to achieve.

The challenges expanded the game beyond simply finishing a song. Some tested instrument-specific skills, such as accurately performing a vocal phrase, while others required score thresholds, Star Power use, whammy-bar control, or other performance goals. Progress appeared on an in-game record meter as the player met the challenge requirements.

The medal names mirror familiar music-industry certification language, but they are not a ranking of song difficulty itself. A Diamond result means the player reached the highest requirement for that particular challenge; it does not necessarily mean the song is the hardest track in the game. Higher-level challenges could require Expert difficulty, although Guitar Hero 5 also allowed mid-song difficulty adjustment in some circumstances. The PlayStation 2 version notably omitted the Challenge feature.