The Debug Room is entered from the Well after praying in version 0.02.5. All the Prayers (including the Broken Sandals and Tall Geta , individually) can be found here. Speaking toFluorette 's 'clone' will also give you the option to decrease or increase your speed, gain money (viewed on the in-game menu, the currency is stated as 'Nat.'), or 'Spin!' which will, upon talking to her again, show the text "DEBUG ROOM WOOOOOOOOOOO". The room also has two grass entrances -- the upper one will take you directly to Monochrome City (page needed), and the lower will take you to GameBoy World.
The Debug Room is presumably for, as the name would imply, finding 'bugs' in the game the easy way by recieving all the effects the game has to offer and playing the 0.02.5 release as a beta player.