The Autobot Elite Guard council building is an homage to the city mode of the gigantic Autobot Metroplex from the original cartoon (The Transformers (1984)) and comics. Alpha Trion can also be spotted in the Autobot Elite Guard's council chamber in some shots. This is the first time this character appears in animated form since The Transformers (1984).
Blurr running with enormous speed on the rings of Saturn (or a planet like Saturn) is a reference to the season 3 intro of The Transformers (1984), which has a shot of the original Blurr racing on Saturn's rings.
The way Arcee's head splits apart in one of Ratchet's flashbacks could be a reference to the comic "Spotlight: Arcee" from IDW Publishing which also featured a similar shot of her opened cranium.
The aliens that turn into rocks are a reference to the Rock Lords from the GoBots movie GoBots: Battle of the Rock Lords (1986). Their head appears to bare some similarity to Bonecrusher's head design from Transformers (2007).
Features the first appearances of: Rodimus Prime, Brawn (has no lines), Hot Shot, Red Alert, Blackout, Strika, Oil Slick, Spittor, Cyclonus (has no lines), Perceptor, Wheeljack (has no lines), Highbrow, Mainframe (has no lines), Alpha Trion (has no lines), and the "upgraded" teenage version of Sari. This is also the first time that Cliffjumper's voice is heard.