I haven't seen much about these online anywhere. Included in the SUBPROG directory are some files for debug tools, such as a model viewer, and a level viewer which includes a small debug system very similar to the second one in Rez and the scud race SDK sample (I think?). I've just been replacing TITLE.BIN with the files, but there are references to some debug features within the title binary. So this is by no means all of the debug features left in the game. I've not had time to fully explore them, but here are some images. Model Viewer (MDLVIEW.BIN) Level Viewer (TEST_0.BIN) Character Viewer (HPVIEW.BIN) Only Sonic, Tails, Knuckles, Amy, Lumina, Illumina and Void can be selected.