Biotics: Eezo is just another form of ADAM. All biotic abilities are simply derivatives of Telekinesis.
Metal Gear Solid's Genome Soldiers are just Splicers waiting to happen, which is probably why the Patriots stopped using them after the first game. That, and their massive incompetence.
No way the whole combining humans and Daleks plan could have ever worked without huge quantities of ADAM. Which explains how the Doctor's Time Lord DNA really got into the hybrids; he just contaminated the ADAM. No magic lightning involved.
Red Flowers: They must be ADAM flowers. And Mimigas have different effects from exposure to it...
The Catalyst: Claire is a perfected little sister (her Healing factor was upgraded by the sea slug). And that explains why the Company gave her to HRG to be a surrogate daughter. They were actually looking for a Protector (Big Daddy) and HRG was their best agent. They somehow knew about Rapture and did not put him through an operation because of the flaws with the Big Daddies. However, this did not stop him from protecting Claire like a Big Daddy.
Nazi Zombies: The technology used by Dr. Maxis was the original form of ADAM, later revised by Brigid Tenenbaum. The Sea Slugs were used long before by Dr. Maxis, although he did not discover the genetic engineering that could be used on the Sea Slugs in order to create the semi-stable (At least for a short while) ADAM, as he quickly, after discovering the healing process, used them on the dead of the Nazi soldiers. They worked, but the soldiers were unstable and could not properly be restrained. Thus you have Nazi Zombies.
The GH.325 Serum. Which means "G.H." is actually a dead splicer, rather than an alien as Coulson theorized. Skye's rather positive reception to the injection suggests a certain affinity for it, which would suggest some sort of connection to the source... Oh my God, Skye is Eleanor Lamb! Which means that her "monster" father who's looking for her is actually a Not Quite Dead Subject Delta! ....And I Need a Freaking Drink.