Endless mode
To get endless mode, you must beat marathon mode by getting 200 lines (or beating level 20). Then an icon will come up in the marathon mode screen (where you can choose the start level) that will say "endless mode".
Grey Blocks
To give your opponent grey blocks you have to perform Tetris's of two or more lines of blocks. So if you get a tetris of three, then three lines of grey blocks are added to your opponents etc. etc.
Make Blocks go Down Faster
When a block is going down get it into the place you want and press up. It will go strait down.
Verified by: this cheat is unverified
Submitted by:
Hao Askura on April 07, 2009
Thinking Time
{to make it up to the later stages in the game, or to just make sure you have the right blocks situated, keep pressing the 'A' button. this will keep the block rotating and keep it from sealing into place. to beat marathon mode, and do well when the blocks are falling fast, use this trick to give you some thinking time. }
Extra Music
You can unlock music (Options > Music) by reaching levels in Marathon mode.
Basement Tetris (Super Mario Bros.)
Clear 20 lines
Mario Tetris 3 (Super Mario Bros. 3)
Clear 30 lines
Bowser Battle (Super Mario Bros.)
Clear 90 lines
DK Tetris (Donkey Kong)
Clear 120 lines
Balloon Tetris (Balloon Fighter)
Clear 130 lines
Tetris Climber (Ice Climber)
Clear 140 lines
Rushed Tetris (Tetris GB)
Clear 150 lines
Ancient Tetris (Tetris GB)
Clear 190 lines
CongriTetris (Tetris GB?)
Clear 200 lines (Finish Marathon)