In January 2014 (approximately), a level briefly leaked in the game's files, under 'hope_diamond/stage2'. This is that level.
What appears is early blockout for what would later become The Diamond, as well as various OVERKILL mission element/unit prefabs.
The level is presented as-is. Only about 12 units are not present on it due to not being present in the game's archives, in order to let it load into BLE, all of which are MKP units. The original files have been preserved in a separate folder, just in case.
Uploaded as a historical resource. The level is not conventionally playable. Files provided by Zdann.