I was wrong, Debug/Level Select are in, you just have to tap S-E-G-A on the SEGA screen and tap the screen with two fingers. Its nice looking.
[spoiler=Debug related goodies]
Items gives choices between "S1" "S2" "S3+S1" and "S3 + S2", choosing S2 Items changes the Shield from the normal one to the one used in S2, and S3 items enables elemental shields (And they all work!), and S3 items at all will also enable Sonic's Insta-Shield.
Debug mode allows the dropping of Monitors that either don't do anything (Emerald Monitor), or are brand new (Spike Monitor, Tri-Elemental Monitor).
In GHZ, Splats the rabbit has been programmed to hop around back and forth (Unlike hacks where he replaces Motobug.) The Wrecking ball works, you can push it around and such, kinda reminds me of Yoshi's Island in a way.
Max Emeralds gives the option between 6 or 7. Don't know if there's a 7th Special Stage though. 7 allows for using Super Sonic/Knuckles/Tails (Yes, SUPER [tornado fang]ing TAILS, No flickies though.). S Monitors work in the same way they did in Sonic 3.
Speed Cap is self explanatory.
S1 Spikes allows enabling/disabling the Spike Bug.
I hear Goggles are in but I'll have to check that when I get to Labyrinth, If the Water Shield is in it probably is so there's that.[/spoiler]