Hints, Cheats and Secrets

Here's a nice list of some hints and cheats as well as a list of Secret Achievement Descriptions (spoilers ahead).

Hints



 - Achievements with no mode stated can be done in any mode
 - Swatches refers to all the drag-able squares whereas Colors refers to all the squares except
    for grey
-  To get more than one answer correct at once, use keyboard shortcuts to place several
   different swatches on the tone scale and press space
 - Become super efficient by using the keyboard shortcuts (especially for the swatches).


Cheats

On the title screen, if you press U followed by L, it will unlock all the features.

Secret Achievements 

Staring Contest:           Keep your mouse over the in-game
                                     Tonestar until he blinks.
Gee Twenty:                 Get a chain of twenty in GreyScale mode
All Grey:                       Try out all the keyboard shortcuts for the
                                     grey swatch in Six mode.
Auto Rainbow:             Using KB Auto, get one of each of the
                                     colored swatches correct in a row.

Refreshed:                   Press Reload and then Reset.
Studious:                      Reach the last page of the Tutorial menu
Luminous:                    Make all the squares in the main game match the
                                    colors found on the first unlocks page (as
                                    luminous / saturated as possible).
Bad Play:                     Get 50 answers wrong.

Multi Eight:                 Get Eight questions incorrect at once ( by
                                    using keyboard shortcuts to place the swatches
                                    on the Tonescale and then pressing space to answer).
Multi Thirteen:            Get 13 questions correct at once
Eighty Twenty:            Get 16/20 for your main score
Spaced:                       Press the space bar 10 times

Short Title:                  Press 2 on the keyboard to continue a save
                                    game on the Title Screen
Blockade:                    Drop a swatch on Tonestar
Monotone:                  Make all the swatches on the main stage the
                                    same tone (easiest to go for black or white)
The NoBW Exp:          Get one question correct on each point
                                    of the NoBW Tone Scale,

Hope this makes Tonestar more fun and useful for you all.