BD is set 20 years after DD, and will explain what happened after the end of DD.
DD2 is in early development, which will presumably pick up where BD left off. It will be in full 3D (BD has 2D backgrounds and 3D NPC models) and have multiplayer support (no details have been mentioned on the implementation).
Also, about the end of DD, posted by Marian in another topic (highlight the text to read);
I would have never thought that the language of pure image is so hard to understand. We have to think about that in the future...
MAJOR SPOILERS AHEAD!
<span class='standouttext'>Spoiler : </span><span class='spoiler'>Ascension "Blessing" cutscene
After you got sacrificed by the council of seven your spirit awakes in a divine realms on an altar. Around you the ideas of the seven gods are manifesting. You can roughly separate impish, human, elven or orcish gods...
Everyone of them grabs into their chest and puts a small part of the heart into your weightless shape. After you received all blessing the <img src="/ubbthreads/images/graemlins/div.gif" alt="" /> in you is fully developed and so her wings grow and she flies up to the mortal plane where she descends as the reborn hero into the wastelands.
You see the demon of lies dying. In fact you see the mutiliated body of janus ripped into pieces and the leftover, the sword of lies, remains. It comes closer and tries to seduce the hero. The hero is tempted to take it but refuses and sends it back to hell away from the mortal plane.
Then the hero hears the cries of the baby. Knowing that it is the lord of chaos inside the child he/she draws the dagger to kill it. In the hero's moral struggle to kill a neborn innocent child the scene fades out.
Much later you see the hero walk out victorious into the swamp area. He carries something. Loot? The child? You don't know for sure...
Somewhere on a distant hill Arhu and Zandalor watch you coming when suddenly the statue you lifted up in the sky while entering the katacombs of aleroth comes down finally...(side joke, nothing more)</span>