Flashback Tape levels are unlocked by finding Flashback Tapes on story levels without dying before obtaining them. They are always unlocked in order. The game has a total of 21 tapes, with the first 11 being playable as Crash, and the latter 10 being playable as Coco. Simply completing a Flashback Level rewards the player a Sapphire Flashback Relic. Breaking 90% of the level's crates earns a Gold Flashback Relic, and a Platinum Flashback Relic for breaking all of them. Collecting all 21 Platinum Flashback Relics unlocks the General Rule skins for both Crash and Coco. Flashback Tapes reuse tracks from the original versions of the first two games as background music.
During "Wumpa Affinity Test", Cortex was revealed to be allergic to Wumpa Fruit. Ironically, Cortex collects Wumpa Fruit in his alternate timeline levels.
In "Outfit Durability Exam", there is a mugshot of Crunch Bandicoot in a TV monitor.
"Subject #272_Final_B" takes place on Crash's birthday (July 19th), as revealed by Cortex.
During "Replacement Considerations", Cortex is torn about having to choose between Crocodiles or Dingos in case his last Bandicoot specimens fail. This is a nod to the creation of Dingodile.
During "The Gauntlet", Cortex will comment about testing on other animals, stating "Maybe next time I'll try a hedgehog... or a bobcat... or a gecko". These are a nod to the platforming mascots Sonic the Hedgehog, Bubsy Bobcat and Gex the Gecko respectively.
There are exactly 3,428 crates in all of the Flashback Tape levels.
The last Flashback Tape for Crash, right before he flees Cortex Castle, is set on September 9, 1996, the day the first game Crash Bandicoot was released.