I've found my last Emblem, and even sequence broke Cannon's Core 3 and 5 with the infinite time switch glitch. No progression items this time aside from a Doom 2 keycard that didn't unlock any checks, with the only Useful item being a Darkra for FF12.
These are the remaining progression items for SA2, please ping me if you find any of them. Anything else for SA2, even another Emblem, is now useless.
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. No hint available for it yet.
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. No hint available for it yet.
Shadow's Mystic Melody (2 Checks): Final Chase 3 and 5. EDIT: Found.
Eggman's Jet Engine (21 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, and Cannon's Core Chao Key 1. Found in Arcaneum's FF12, in Nabreus Deadlands - Nabreus Medallion 2 Reward (1)
Rouge's Mystic Melody (7 Checks): Dry Lagoon 3 and 5, Egg Quarters 3 and 5, Egg Quarters Chao Key 3, and Mad Space 3 and 5. No hint available for it yet.
Yellow Chaos Emerald (59 Checks): With this item, I can clear my goal and release my game, and the above five will all be meaningless. Found in PoryKid's Mario and Luigi, in Joke's End - Northeast of Boiler Room 2 Block.
As for my Doom games, Doom 1 now only needs 8 more levels unlocked, and 14 more keys. (Excluding Command Control's two keys and Against Thee Wickedly's yellow skull key, which are now useless)
Doom 2 has 11 remaining levels to unlock, and 14 more keys left to find. (Excluding the Blue Keys for the Gantlet and the Citadel, which are now useless.) I will also need my Rocket Launcher to meet my goal.