Learning the Basics

How do I play?
While most PC users won't have a touchscreen at their disposal, this game is made to be playable with a normal mouse, as well as any number of input devices you can possibly think of. There are some songs which push the limits of the normal mouse (and you), but all the (ranked and approved) beatmaps have been tested and (most can be) passable using only a mouse.

Gameplay Basics
The gameplay puts emphasis on your:
 * Adaptability and reaction to stimuli (that is, the hit-able objects appearing all over the screen at lightning speed).
 * Understanding of the song beat and design.
 * Your control of your mouse (or your fingers/pen-poking skills if you are using a tablet instead).
 * Timing of your hits on the object that appeared on the screen.
 * Ability to spin the mouse (or your finger/pen for tablet) on spinners.
 * Your physical stamina (especially marathon songs).
 * Proper mouse positioning and hand-eye coordination.
 * Your hardware capability (especially your mouse/tablet).

Hit Circles
thumb|150px|link= The smaller coloured approach circle on the outside shrinks and you have to hit the note at the exact point when it touches the white border of hit circle.

To understand the hidden charm of hit circles, you should not only rely on your perception (your eyes) but also the understanding of the beatmaps' beats and rhythm by your ears (auditory).

Sliders
You have to hit the slider at the right moment, but it doesn't end there.A ball will start to move across the path you see.You have to hold the mouse/keyboard-button (or your finger/pen on the tablet) and keep your pointer inside the thick orange circle surrounding the ball as it moves.

You cannot control the movement, and you must follow its movement.The orange circle will appear if you are holding it and disappears when you leave it.

Sometimes, you have to move back at the end of the path.You can tell by the reverse symbol at the end of the path.

Spinners


You have to click then hold the hit-button, and the mouse is used to spin (clockwise or counter-clockwise) in circles as fast as you can before the time (which is, that blue circle line) runs out.

The bars on the outside indicate how close you are to passing.The small bar below the spinner shows spins per minute, means the number of spins you are making if you continue that speed of spinning for one minute.If you didn't hold any hit-button prior to spinning, you will not fill up the gauge at all.

On the DS, this is a good way to scratch your touchscreen (or screen protectors), especially on the higher difficulties.In osu!, spinners have been toned down as to not be such a nuisance to complete.

The maximum number of spins per minute achievable is 477 which is also the rate at which the Auto game modifier spins while the Spun Out game modifier spins slower at 287 spins per minute.

In-Game Interface
The top left bar is your "health". This will decrease at a steady rate[(depending on the beatmap difficulty set by the mapper(s)], but you can replenish it by hitting notes at the right time.

A perfectly timed hit (300 hit or Geki Beat) will increase your health more than a badly timed hit (50 hit).A total miss will take a good chunk out of your health.

Next to the health bar (at the right) is your score.Below the score is your accuracy.The circle beside your accuracy and below your score is a timer bar, which shows the song length.The number on the bottom left is the combo counter/score multiplier.

Explaining "Taiko"?
Hit-circles This will appear as either a red or a pale-blue circle. They are named as red (Don) notes and blue (Katu) notes. If it is a small red note, you must press the button bound to the inner portion of the Taiko drum or hit the large flat area (center) of the TaTaCon. If it is a small blue note, you must press the button bound to the outer ring of the Taiko drum or hit the sides of the TaTaCon. If the note is a LARGE circle, you should press or hit both of either inner or outer drum depending on the colour of the note for additional points.

Players can also only press one of the inner or outer drums and still get points, but not as much as when you hit both of them. The notes must be pressed or hit when they reach the small white circle next to the drum below the status bar on the play-field.

Hit balloons

They are shown as normal small red notes but with a inflatable balloon behind it. You should hit the inner drum continuously until the hit counter reaches zero. You gain points for each hit and bonus points for popping the balloon.

Drum rolls

Drum rolls appears as yellow bar in the play-field. You should hit the inner (or outer) drum continuously until it is done. For LARGE note, you should hit both buttons on the inner (or outer) drum simultaneously and continuously until it is done. You gain points for each successful hits. You can choose to ignore it at the cost of your possible points gained from the drum roll.

Dendens

These appear as spinners, with a countdown displaying the time you have remaining to clear it. You must hit the inner and outer drum in order (like red,red, blue,blue, red,red, and so on) until the Denden meter is full. Bonus points are given for extra hits after completing the Denden.

Controls

 * The default controls for the Taiko mod are:


 * Red: [Mouse] Left click, [Keyboard] [X] or [C], [TaTaCon] Flat surface of the drum.

Blue: [Mouse] Right click, [Keyboard] [Z] or [V], [TaTaCon] Outer surface of the drum. osu! cursor placement does not matter when playing.


 * You may configure the keyboard buttons as you see fit, from the Input tab in the Options menu.

Explaining "Catch the Beat"?
Catch the Beat (also widely known as CtB) is the second special game mode to be added in, after Taiko game mode. Instead of clicking circles, you are now tasked to move the catcher at the bottom of the screen while the fruits fall from above.

Controlling the catcher

 * If the Relax mod is used, control of the catcher is done by moving the mouse instead.
 * By default, the left [<-] and right [->] arrow keys are used to move the catcher.


 * Pressing the left [SHIFT] key with one of the arrow keys will make the catcher dash in that direction at x1.5 speed (indicated by a bright glow at the catcher).

Explaining "Osu!mania"?
Osu!mania is the third special game mode to be added in, after Taiko and CtB game mode. This mode has been widely used in almost all of the major rhythm games that require good hand coordination, where the beat notes with their quantity depending on BPM (beats per minute) and difficulty move on the conveyer, and the player have to press the correct key for that specific beat note in time.

Though the game mode was originally made as an imitation of Beatmania style of playing, however, by changing the number of keys, you can make it look more like Guitar Hero or Dance Dance Revolution and so on. Currently, you can set from 1 to 9 Key by game modifier (by default, it would be around 4 to 8 Key, except for osu!mania-specific beatmaps) to an upward of 2 - 18 Key (two playfield) with the Co-op game modifier.

Controls

 * There two different binding-styles, Symmetrical and Left to Right.


 * Symmetrical style mimics the button placement of DJMAX, in which the center key is "spacebar", in which, created a feeling of "stepping" the pedal similar to the arcade version. Centre key matches the middle column (5K and 7K only) and the other column matches the keys in its corresponding place.


 * Left to Right style mimics the button placement of Beatmania IIDX, where the first column matches to the key1, then the second column matches the key2 and so on.

Symmetrical key binding (For DJMAX style)


 * For left hand buttons — K1 - A, K2 - S, K3 - D, K4 - F


 * For right hand buttons — K6 - J, K7 - K, K8 - L, K9 -  ;


 * Center button — (K5)spacebar. [On 5K and 7K only]


 * The Special button — left SHIFT and left control "Ctrl".

Left to Right key binding (For Beatmania IIDX style)


 * From down to up then down to up again: K1 - Z, K2 - S, K3 - X, K4 - D, K5 - C, K6 - F, K7 - V, K8 - G, K9 - B [K9 is not used]


 * The Special button — left SHIFT and left control "Ctrl".

Performance Points (pp)
Performance Points (pp) is a ranking metric aiming to be more contextually relevant to a continuous game like osu!. It aims to shift the focus from being on the amount of time played to the actual skill of the player. Performance points are heavily based on map difficulty which is determined by a unique algorithm in every gamemode. Based on this difficulty alone each of your scores is rated and assigned a pp value. Your performance rank is predominantly based on your performance on individual maps. The easiest way to improve it is to improve your scores on difficult songs. Do note that game modes are counted separately [which means, playing (osu!/Taiko/CtB/osu!mania) raises (osu!/Taiko/CtB/osu!mania) pp].