As many of you May know Arkham Asylum has three Alternate endings based on how many challenges you completed:
2. Killer Croc having escaped into Gotham Harbor via large hole Batman blew out of the sewers grabs onto a Titan Crate.
3. Bane having been knocked into the Harbor by Batman earlier rises out of the water and grabs onto a Titan crate.
Now then Allow me to post My theories of how these Alternate endings will relate to Batman: Arkham City. Via a downloadable content feature 3 new missions will be unlocked one for each ending:
1. Scarecrow earns funding for his research via reverse engineering, mass producing and selling Titan to the other crime lords, and when confronted by Batman injects himself with the drug transforming himself into his "Scare beast" form.
2. Killer Croc injects himself with Titan further excelerating his mutation (note that the Venom Compound also excelerated his mutation when he was first injected).
3. Bane already knowing how to create Venom also mass produces Titan and uses it on himself and his gang.
And as I've recently learned from the comic book series Bridging Arkham Asylum and Arkham City multiple crates made it to the mainland, meaning it's possible that all three endings are Canon.