If you don't want the background grid hold LT + LB + RT + RB and press B to remove it.

To be able to do this hold LT + LB + RT + RB and press A.

Unlock Hyper Mode:
Complete 8 levels in Action mode.

Unlock Twilight Mode:
Complete 17 levels in Classic mode.

Unlock Cognito Mode:
Complete ALL 80 Puzzle mode worlds.

Unlock Finity Mode:
Complete 280 levels of Endless mode.

Unlock Original Mode:
At the 'Main' menu go to the 'Play Game' option and select the following features in order; Classic, Action, Endless, Puzzle. After a few cycles the message 'Please Wait' will appear on screen and a version of the game similar to the original Bejeweled will start.

Complete the following tasks to get the corresponding achievement.

Cascade 8:
Get an x8 Cascade. Finity Mode:
Reach level 9 in Finity mode.

Classic Mode:
Reach level 18 in Classic mode. Cognito Mode:
Get 50,000 points in Cognito mode.

Action Mode:
Reach level 9 in Action mode.

Hyper Mode:
Reach level 9 in Hyper mode.

Puzzle Mode:
Complete level 80 in Puzzle mode.

Twilight Mode:
Complete level 10 in Twilight mode.

Endless Mode:
Complete level 280 in Endless mode.

Hyper1000:
Make 1,000 Power Gems total with the games.

Power10000:
Make 10,000 Power Gems total with the games.

Multi Mode:
Unlock Twilight, Hyper, Cognito and Finity modes.