Dotstream is essentially a side-scrolling racing game, where you are a blinking dot which leaves behind a colored trail.
There are three different game modes. The first available is Campaign which are a circuit of races. Each finish gets you points which add up. At the end the racer with the most points from each competition wins the circuit.
Second is Spot Race, which takes the tracks from the campaign, but allows you to race them one at a time.
Finally, Formation, which is considered a "performance" where you have to collect a series of dots which will fill up a meter at the bottom of the screen that is broken up into sections. When a section fills, you get another line to control. Your goal is to keep this up as long as you can.
Campaign and Spot Race Gameplay
Your dot goes automatically, you do not have control over any acceleration. However, the B button will allow you to slow down. Along with your dot there are 5 other racers you are competing with. They too leave behind a colored trail, and if you are behind them, you can never ride on the exact same path. If you try, you will automatically be pushed off to an empty space.
Although you can't accelerate, you can control the speed of your dot, which is based off of the straightness of your line. Every time you press up or down to allow your dot to avoid obstacles, of which there are many, you slow it down. Repeating levels allows you to discover pixel sized paths where you can stay on a straight line and avoid, sometimes just barely, all obstacles.
You can also hit the R button to give yourself a boost. You have a limited number of boosts, which are represented by a diamond in the bottom left corner of your screen. You start off with three, and each time you use a boost you lose a diamond. This number also represents how many times you can hit an obstacle, so if you crash, you lose the opportunity for a boost. If you have no more diamonds, you cannot boost and if you crash, you are out of the race.
At the end of a lap there is a pit stop type area located right before the start-finish line which will stop you but will bring you up to a total of 9 diamonds.
There are other objects you can hit which are not considered obstacles, for example an arrow which will speed you up temporarily, and another looks like a skid mark and will slow you down. There are also objects which look like obstacles but are filled with tiny dots. These obstacles you can pass through, but will slow you down.
The A button is what lets you use any power ups which you can gather during races. Examples of these are a portable boost and one that slows down time temporarily so that you can navigate obstacles.
In formation, the controls and idea are the same, however you are not racing against anybody. Instead your goal is to collect dots which allow you to add a second line. This line is added when you collect enough dots that the meter on the bottom of your screen, which is broken up into multiple sections, fills up one of those sections. Then a second line appears.
That second line is controlled with the A button. If you do not press A down the second line will continue to go straight and you are only controlling the line you have. Holding down A will cause all lines to mimic the movement of your line. Your goal is to keep this "performance" going as long as you can.
In this mode you also can't use your B button to slow down, nor is there any boost. Along with that your penalty for hitting an obstacle with either line is a portion of your meter at the bottom goes away. When the second section is completely gone, you lose your second line. If you lose the first section too, then your game is over.
Once you fill up a third second, and fourth, and so on, then even more lines are added.
The screen is broken up into sections which give you information about your current race.
The top of the screen is split up into three sections. The left has your current lap / how many total laps. The center shows a full version of the track which a vertical line representing each dot's position. The far right has your time.
The center is the race field. The very bottom portion of the race field contains a pit stop area before the start-finish line. The actual pit portion is the diamond.
The bottom area is broken into two sections. The left shows how many diamonds you have left, which represents how many more crashes you can sustain and/or how many boosts you can use. The center is your speed. Normally you are on half full. Hitting B to slow down will bring you to a quarter full. Using a boost will bring you up to 100% full.
Although Dotstream is a Japan-only release, the game is completely in English. The manual, however, is not.