This page goes into depth about the early, developmental stages of the game Bedrock. If you were looking for the summary of all versions, go to Version History.
The entire contents of version dev_0.0.0 consisted of a cube with the meme Don't Look at This Chicken displayed on all six sides of it.
Dev build 0.0.1 added a couple of new features, such as the underlying block-world structure, and two types of blocks: dirt and water. Water is a solid, opaque block in this version. Lighting had not been implemented, meaning that all sides of all blocks appeared to "glow". This made it very hard to distinguish terrain features in early dev_0.0.2.
Version dev_0.0.2 added simple random terrain generation. Other than that, it mainly dealt with some simple mechanical fixes, such as adding fog and shading, and making terrain look like it is illuminated from a fixed location, unlike previously in version dev_0.0.1, where everything looked strangely flat.
Version dev_0.0.3 made the world generate like a floating island, and introduced rocky dirt and stone. Two bugs were fixed, such as chunks rendering in the wrong place, and textures being displayed incorrectly.