An update came out for the game today, (I think) December 6th, this may
fix the problems people are having unlocking this.
------Important note: There is curently a glitch in which you have to play more battles than required in order to unlock this achievement. I have yet to figure it out but it may or may not be related to the following:
If flashcards dissappear during a battle.
- Checked again, this doesn't matter.
If the other player is signed in. - This DOES matter.
If it has to be 20 unique/different songs.
If DC export and DLC songs count. - DLC counts, DC won't always count.
If you already have a score on the song in Perform It.
- Doesn't matter
If you are online.
- Doesn't matter.
If it is win 20 songs in a row or one session.
Waiting for the crown to appear at the results screen and for the game to save before continuing.
If the winning player must be ahead in score at all times during the song.
When I unlocked it, the other player was signed and only my profile got it.
This one requires a second player, a cardboard cutout does not seem to cut it (don't ask). However all you have to do is win, which means your "friend" can simply stand in place while you rack up points.
First thing to note is that Dance Battles are much longer than the original song in Perform. So make sure not to tire yourself out by doing this.
Secondly, difficulty does not affect how you score. Someone playing on Easy will score just as much as someone on Hard if they play just as well.
Solo part: x2 multiplier for your moves.
Free-4-all card: 10,000
Free-4-all gold card: 40,000
Also, make SURE you are playing as the profile who wins the match, and actually win the match. If you haven't set up Kinect ID for yourself (or haven't got one) the game has a habit of switching you around.
One glitch that came up from time to time was that there would be no flashcards after a Free-4-all, but you are still required to play through the song. I couldn't figure out a way to make them instananeously appear back, so you might as well live with it until it is fixed. They'll come back for you if and once your opponent finishes a solo part.Shortest songs
These are the shortest songs on disc, in terms of number of moves rather than song length.
"Whip My Hair"
"Oops (Oh My)"
"You're A Jerk"
"This Is How We Do It"
"Get Ur Freak On"