Pencil2D is an open source and multiplatform tool with which it is possible to draw and generate 2D animations.
Pencil2D is not intended to compete with Flash, although the animations are based on keyframes and different layers. Unlike Flash, in Pencil2D it is necessary to draw by hand each of the frames that make up the animation.
There are four layers that Pencil2D allows you to create: bitmap layer, vector layer, sound layer, and video layer. In each one you must place the corresponding elements to obtain the animation.
The Windows version does not yet allow exporting animation to video, a feature that is available in other operating systems such as Macintosh.