Easter Eggs

Kane and Lynch may be encountered by 47 in separate chapters,Welcome to Hope and Birdie's Gift. Although you can kill either character, the "doctrine" storyline likely has both parties mutually unaware of one another.

Another time Kane is spotted is during the Holding Cells section of the Courthouse mission. There is a vent that leads to the door to the next section. Crawl through the vent from the room before it and you can view him through the vent. Kane can be seen in a room writing a letter to his daughter.

Missing Saint

In the "All Saints" trailer for Hitman Absolution, there are clearly 8 Saints attacking 47's hotel.

You can, in fact, see the thumbnail in Attack of the Saints displaying a frame from the video.

 

However, the actual in game mission only features 7 targets (LaSandra Dixon, Jennifer Paxton, Heather McCarthy, Dijana Radonic, Agnija Radonic, Louisa Cain, and Jacqueline Moorhead). So, the question is: What happened to the 8th Saint?

Apparently, at timecode 00:52 in the ICA file video of the Saints, one of their team is shown to have been killed before the events of Hitman Absolution (so who the heck was in the "Attack of the Saints" video? It's a ghost!).

The eighth Saint is known only as "Boo."

Lochness Monster

Lochness Monster in the tutorial mission: When you get inside the building where you need to make your way to Diana, head into the main room (Where the head of security and the grand piano are) and head to the second floor. Hit the button that rolls up the window curtains, then shoot the two seashell sculptures. Look out the window towards the lake and enjoy.

Blood Money Easter Eggs

On the level "One of a Kind",  head through the door behind the counter. In the basement, if you go straight, you will find three mannequines each in unique disguises. However if you turn to the back left corner of the room, you will find another disguise: the Bird Costume from the Hitman Blood Money level "Murder of Crows". Also, if you look on the wall to the right of the three mannequines, you will see newspaper clippings from Blood Money levels.

Ice Cream Truck Easter Egg

In the level "End Of the Road", you will notice that they're 5 birds. Get them in the air by walking towards them. Then, when all the birds are airborne, shoot all them and you will recieve a special surprise.

Nuke Easter Egg

In the level "Dexter's Industries", where you enter the main building (Where all the mines are displayed), look up and you will see a large bomb. Shoot the bomb a few times to get a cutscene. (Note that this effectively ends 47's mission as a failure)