=== EDIT ==
The new version of PSB is coming in May - June! Sorry for the delay but it'll be awesome!

Platform Sandbox
After a month of toiling away at Flash, the new version of Platform Sandbox was made.

New features!

> Made with Swift3d ( You may not notice the changes, but if anyone PMs me, I'll give 'em the moviclip that never made it into the game. If you decompile it, you'll find the animation. Or you can just download the source code )
> Now you can add more than a certain number of things! For example, you can add as many spikes, coins, and signs!
> The toolbar doesn't interfere with the playfield.
> Jetpack!
> Fuel!
> Spikes!
> Magnets!
> Smaller file size!
> Fixed the jump bug!
> Locked doors!
> Lava!
> Water!
> Ice!
> Status effects!
> Health bar!
> Play and pause (originally it was for you to edit the game without getting mauled by the tanks, but now it's to plan what you are going to do, and to pause everything for, let's say, a coffee break)
> Id card to open locked doors!
> Four way spikes (up, left, down and right) in place of tanks
> Now you can change the gravity for the area (in pause mode) from Earth to Moon, and from Moon to the Earth!
> New physics engine!
> 80% of bugs destroyed so you can have a fun experience!

Instructions: ( see the website for more info )
Left and right arrow keys (in play mode) : Move left and right respectively.
Space key (in play mode) : Jump up.
CAPSLOCK button (if jetpack is unlocked) : Fly!
Arrow buttons near toolbar (They're blue ) : Change the type of entities to place on the PlayField
Status effects :
If you come in contact with water, it induces the Cold status, but evaporates if you have the Heat status and neutralizes the Heat status.
If you come in contact with lava, it induces the Heat status, but evaporates if you have the Cold status and neutralizes the Cold status.
If you come in contact with ice, it doesn't induce anything but it melts into water if you have the Heat status.
Status effects decrease the character's HP! Watch out for your health.
Press the S key for the fan
Press the C Key (in pause mode) for dragging the character.
Play and pause mode : Click on the button which has a triangle ( at the top left corner ) to start. Press the same button ( its changed to a pause button ) to pause.
No more cheating, as you can't edit levels while playing.

Here is the original help file from http://platformsandbox.yo lasite.com/help.php (for convenience):

1) Use the left and right arrow keys to move.
2) Select a block (it's at the bottom, the rectangle with a lot of blocks) and click on the grid to add the box to the PlayField.
3) Click on the left and right arrows (they're blue, and near the rectangle) to cycle through the selection.
4) To add an extra (the coins, spikes, black hole, etc) see step 2.
5) Click on the Play button ">" at the top left corner to start the sandbox.
6) Click on the same button to pause and reset the gravity and status effects.
7) Press the SPACE key to jump. Note that you can jump only if the gravity is either UP or DOWN.
8) Gravity changers (the arrows) change the gravity according to the direction they point to, ie ">" gravity changer changes the gravity to "right".
9) Status effects occur when the character you control comes in contact with certain elements.
10) Water induces the cold status, and cures Heat if it is present. It also evaporates if Heat is present.
11) Lava induces the Heat status, and cures Cold if it is present. It also evaporates if Cold is present.
12) Ice turns into water if the character has the Heat status.
13) Status effects decrease the character's HP.
14) Press CAPSLOCK to activate the jetpack.
15) The formula for "lift" is ( Gravity + 1) * 1.5
16) Press S for the Fan.
17) Press and hold the C Key to drag the character.

~ Gimmick