Tetris DS features several modes that utilze the original tetris format in different ways. Each mode features an animated tutorial that explains while a game goes on.
Standard[edit]
This is similar to the original Tetris with no special twists; You simply rotate the tetriminos and fit them into horizontal lines. There are several themes, but the main one is Super Mario Bros..
Marathon[edit]
After clearing certain amount of lines, the character animation on the top screen changes. Every horizontal line you clear counts as one line. Every 10 lines you clear moves you up to the next level. If you beat Level 20, you unlock the Endless mode, which lets you play forever. Every level is an etch faster.
Line Clear[edit]
Similar concept to Marathon; clear lines to make the character at the top move. The difference, however, is that you have a certain amount of lines to clear. You can set 2 things before the match; the Level and the height. Level changes how fast the blocks fall, while Height changes the amount of junk blocks that the game starts off with. The higher the both of those are, the more points you get.
Vs CPU[edit]
The title explains the purpose. It's simply a game of tetris against a computer simulated opponent. The speed of the computer is affected by levels. Levels range from 1 to 5, with 1 being the weakest and 5 being the strongest. In competitive Tetris, whoever reaches the top first loses. You gain the ability to send "New Blocks" to your opponent. New blocks are lines of gray tetris pieces missing one block (so the line doesn't automatically clear). Clearing 2 lines sends 1 new block line, Clearing 3 lines sends 2 new block lines, and clearing 4 lines sends 4 new block lines. If you get "Back to Back TETRIS", then it will send 5 new block lines.
Catch[edit]
Catch only has one mode; itself. The theme is Metroid.
Catch[edit]
Catch mode is different from the usual tetris formula because you control one tetrimino block, and stack the tetris pieces onto it. Instead of clearing lines, you want to line up an area of 4x4 tetrimino blocks. If you rotate the blob into a tetrimino piece (which breaks it), let a piece hit the ground, or crash into a metroid, you'll lose HP. When you have at least a 4x4 area, that area of tetriminos turns white for 10 seconds. At this point, you want to increase the size of the block with more tetriminos. When the 10 seconds are over, the block explodes and you get a surplus of points. It ends at Level 20.
Push[edit]
Push mode only has one mode; Vs. Com. The theme is Donkey Kong
Vs. Com[edit]
This has a similar concept to Vs. Standard mode except for one huge difference: Both players are on the same screen. The goal is to push your opponent to the bottom of the screen (both players see themseleves as the second screen). The computer's level can be adjusted from 1 to 5, with 5 being the hardest. The more lines you clear, the farther in your enemy's direction it'll go. If you are pushed to the top, you lose.
Mission[edit]
Mission has 2 modes; Marathon and Time Trial. The theme is The Legend of Zelda.
Marathon[edit]
This mode uses the tetris format, but is not about clearing lines. The game will give you certain tasks to accomplish (Clear 2 lines at once), and if you do not finish them in the allotted time limit,4 new block lines will form. If you do complete the task, however, the game takes away 4 lines of blocks. Every 2 tasks you complete moves you up a level, where the time is less and the tasks are harder.
Time Trial[edit]
Same concept as Marathon, except the goal is to complete the 10 tasks they give you as fast as possible. There are no new blocks. This mode has 5 levels; each level has substantially harder tasks, with 5 being the hardest.
Touch[edit]
Touch has 2 modes; Tower and Puzzle. The theme is Balloon Fighter.
Tower[edit]
There is a bunch of Tetris pieces stacked upwards, and you want to clear them all. At the top of them is a box of balloons at the very top. When that touches the ground, you win. Levels 1-3 allow you to rotate blocks, but 4 and 5 do not.
Touch Puzzle[edit]
Each puzzle has a task for you to complete. They start easy, but slowly get tougher. You can't rotate the blocks. If you mess up, simply tap retry and try again. There are 50 puzzles.
Puzzle[edit]
Puzzle has one mode; itself. The theme is Yoshi's Cookie.
Puzzle[edit]
Tetrimino lines are set up in a way that puting key tetriminos in the right spot would clear all of them. To play, simply choose a block and the direction you want it to drop. The tetrimino will then drop automatically. There are 200 puzzles. They start easy, but become progressively tougher.