A docstyle video to summarize early design and gameplay elements that were much more impressive compared to the final product. Infinite went through many revisions over the course of its development, Irrational Games had to scale back a lot of ideas, which was disappointing for a lot of people after the E3 showcases. Everything shown here has been removed or downgraded to the point where it's just not comparable. Selfexplanatory quote from Ken Levine: "we cut enough content to make 56 full games". There's more in the official artbook if you're interrested.

Sources
Early Gameplay Demonstration    • BioShock Infinite Early Gameplay Demo...  
E3 2011 Gameplay Demo    • BioShock Infinite E3 2011 Gameplay Demo  
About SkyLines    • BioShock Infinite: About SkyLines  
Factions at War    • BioShock Infinite: Factions at War  
Windows Into Other Worlds    • BioShock Infinite: Windows Into Other...  

Key moments
0:01 City of Columbia
2:35 Tears
4:32 Skylines
6:13 E3 gameplay