DD2 Cheat Menu:
To access the level editor, press Control U on the main menu screen.
To access the in-game cheats, press Control U in game.
To access the item summoning cheats, press Control U while on the character inventory screen.
The walkthrough file is available for download (note that it currently only contains walkthrough for the first 20% of the game. The walkthrough will be updated shortly to assist playtesters).