Master level difficulty 
To unlock as master difficulty, get an A rank in one of the tracks. You will then 
have a new difficulty level. It is (as far as I can tell) exactly like hard mode but 
with less warning when the heads will appear.

Track 21-25 
Complete tracks 1-20 all the way through on any mode 

Bonus tracks:
Play all twenty tracks to unlock a further five tracks to keep you occupied. The 
bonus tracks are Gotta Get Through This (Daniel Bedingfield), Keep On Moving 
(Five), Aserjeré (Las Ketchup), Rubberneckin (Elvis Presley), and Addicted To Bass 
(Puretone). 

Score big:
To score big, play perfection in the tournament mode against another player. This 
will hopefully improve your timing. 

Home-made games:
The following is a list of fun games you can invent to keep the groove going. They 
are best played with two or more players.

Perfection: 
The person with the most amount of perfects wins; points are irrelevant. 

Battle Of The Gods: 
Play "Praise you", "Rubberneckin", and "Addicted to Bass" all under the hard 
difficulty setting. The player with the biggest score out of those three rounds 
combined wins. Note: This requires the bonus tracks. 

Danceathon: 
Play all twenty five songs in a row on any mode. The player with the biggest score 
out of all those rounds combined wins. Note: This requires the bonus tracks. 

Goldie Oldie (in order of age): 
Play "Dance To The Music", "Jungle Boogie", "YMCA", "We Are Family", and "Let's 
Groove". 

New Years Groove (all new songs released in 2003 in order of track appearance): 
Play "Jumpin", "Hooray, Hooray", "Hustler Groove", and "Rubberneckin". 

Dance Like Hell: 
Play "Addicted To Bass" in master mode. You will not last long, but the idea is to 
see how long you last. 

Pain In The Neck: 
Play "Praise You" in master mode. 

Drybone: 
Set up calorie mode and burn at least 10, 15 or 20 calories. 

Songs:
Unlock Songs 23-28 by completing the first 23 songs on any difficulty.