A.I. Is a Crapshoot: The T-Pod. Donnie put an advanced military-grade AI chip in it, which allows it to upgrade itself continuously. It's harmless as an mp3 player, but becomes a crapshoot when Stockman hooks it up to his Powered Armor.
Amusing Injuries: When Splinter catches the turtles sneaking home late, they're all covered with very obvious injuries. Said injuries all disappear by the next scene.
Blade on a Stick: Donnie tries using the naginata blade on his staff for the first time, only to have Stockman break it the minute it pops out.
Composite Character: Baxter Stockman, while black like in the original comics and 2003 show, appears to take visual cues from the 1987 version of the character in hairstyle.
Cut Himself Shaving: When Splinter catches the battered turtles sneaking in late, he asks what happened. After a few minutes of stuttering while trying to come up with an excuse, Mikey says they got hit by a bus. Splinter, of course, isn't fooled for a second.