Update April 17th - GOG.com is now taking pre-orders for The Blackwell Epiphany as well. As a bonus for pre-ordering from GOG.com, you'll get a GOG.com exclusive extended demo of the game, as well as the other pre-order perks listed below (minus the Steam key, of course).
Original post from April 1st - The Blackwell Epiphany, the fifth and final game in the Blackwell series by Wadjet Eye Games, is scheduled to be released on April 24. The game is up for pre-order now for $14.99 USD from the Wadjet Eye Games store. People who pre-order will get additional bonuses once they become available: behind the scenes videos, access to the video feed for the virtual launch party, the game's soundtrack, and a Steam key for the game. When the game is launched on April 24th, it will be available from the Wadjet Eye Games store, Steam, and GOG.com.