In Slime Roll by ThatOtherDev you control some green stuff that falls down and you can rotate the world to make it fall in a different direction and in doing so you can get the green stuff to navigate the world. There is a built in level editor.

Changes:

* The red circles have been removed and replaced with blue ones that are of a consistent size.
* If slime comes in contact with a blue circle then the blue circle becomes slime.
* There is on screen text that tells you how many blue circles still exist.
* When placing slime in the editor you no longer need to press and release the button for each piece of slime.
* There is a limit to how closely you can place two pieces of slime together in the editor.
* The same rules for placing slime in the editor also apply to the blue circles.
* You can now delete whatever object you are pointing at in the editor (instead of only being able to delete the last thing spawned).
* The X in the editor has been replaced with a proper reticule.
* There is a slightly nicer title at the menu.
* All on screen text fills the same percentage of the screen regardless of resolution.
* I’ve fixed the problem where there would sometimes be inappropriate white pixels along the edges of circles.
* Gravity is slightly stronger.

http://thatotherdev.com/2011/09/06/slime-roll-v0-2-–-ps3/