And I got you 2 more Emblems by the way
@Explorer of Time!
Thank you so much! These emblems unlocked a ton of new checks in SA2. I found a Heart Vessel for Setsuna, a keycard for a Doom 2 level I don't have yet, some Emblems for Arcaneum and myself, and, most importantly, the 6th Chaos Emerald. I only need one more to enter Go Mode in Sonic Adventure 2, which is in PoryKid's game.
While waiting for that Chaos Emerald, I can still get more checks if I get certain items. These are:
Sonic's Bounce Bracelet (7 Checks): City Escape - Upgrade, Crazy Gadget 5, Final Rush 1, 3, and 5, Final Rush - Upgrade, and Final Rush Chao Key 3. All accessible without other upgrades.
Tails' Bazooka (7 Checks): Prison Lane - Upgrade, Prison Lane Chao Key 1, Prison Lane 5, Eternal Engine 1, 3, and 5, and Eternal Engine Chao Key 2. All accessible without other upgrades.
Shadow's Mystic Melody (2 Checks): Final Chase 3 and 5. Both accessible without other upgrades.
Eggman's Jet Engine (21, 23, or 24 Checks): Iron Gate 3 and 5, Sand Ocean 3 and 5, Sand Ocean - Upgrade, Lost Colony 1, 3, and 5, Lost Colony Chao Key 3, Weapons Bed 1, 3, and 5, Weapons Bed Chao Keys 2 and 3, Cosmic Wall 1, 3 and 5, Cosmic Wall Chao Keys 1, 2 and 3, Cosmic Wall - Upgrade, Cannon's Core 3 and 5, and Cannon's Core Chao Key 1.
Cannon's Core Chao Key 1 requires another Emblem, and Cannon's Core 3 and 5 require both an Emblem and Rouge's Mystic Melody.
@Arcaneum Since the Jet Engine unlocks the most checks, I've hinted for it. It's at Nabreus Deadlands - Nabreus Medallion 2 Reward (1) in your FF12. I can beat my game without it once I get the Yellow Chaos Emerald from PoryKid's game, though.
Rouge's Mystic Melody (7 or 9 Checks): Dry Lagoon 3 and 5, Egg Quarters 3 and 5, Egg Quarters Chao Key 3, Mad Space 3 and 5, and Cannon's Core 3 and 5. The two Cannon's Core checks also require one more Emblem, and Eggman's Jet Engine and Mystic Melody.
Emblem (3, 4, or 6 Checks): All six Cannon's Core checks. Cannon's Core 1 and Chao Key 2 and 3 are accessible with only this, while Chao Key 1 requires Eggman's Jet Engine, and Cannon's Core 3 and 5 also require Rouge's Mystic Melody.
EDIT: I sequence broke most of Shadow's lost chao levels, so his Mystic Melody is only necessary for two checks in Final Chase. Both are technically sequence breakable if I can make a specific jump, but I'm not skilled at spindash physics exploits so it's basically impossible for me to get them without his Mystic Melody, at which point I can get them both easily.
EDIT 2: Obtained Eggman's Mystic Melody.