Alternative Character Interpretation: Talia may be lying that the Lazarus Pit won't revive Ra's. After all, given her often tumultuous relationship with him, it might have been a good opportunity for her to eliminate him for good. She is, after all, willing to drug Batman to conceive a child. Also, as Batman himself notes, she doesn't seem to be very broken up about Ra's death.
Base-Breaking Character: Both Damian Wayne's scrappydom and fandom start here. On one end he's a scrappy due to being extremely unlikable and performing extremely improbable feats for a kid his age, while on the other hand it's clear he's being set up for greater Character Development over the course of the Animated DCU. It's up to the viewer to decide whether they enjoy him or not.
Complete Monster (includes Teen Titans: The Judas Contract): Slade Wilson, aka Deathstroke the Terminator, slaughtered many League of Assassin members when Ra's al Ghul selected Bruce Wayne as his successor instead of Slade. Taking Bruce's son Damian to keep him in line, Slade torments Damian by making him watch his mother be tortured and later tries to kill Bruce's whole Bat-Family. Saved by Brother Blood and recruited to bring him the Teen Titans to drain their life force for Blood to empower himself, Slade sends Terra Markov—a teen whom he raised as his lover and pet assassin—to infiltrate and betray the Titans, and when Slade's contract requires a Titan sacrifice to replace a lost one, happily tries putting Terra to a painful death.
Just Here for Godzilla: Some are here just for another animated Nightwing appearance or for Damian, whose comic counterpart was dead at the time this movie was released.
During Slade's attack on Ra's' fortress, you can see one guy literally just... stop when a Slade mook is pointing a gun at him and try to block it instead of, you know, just killing him. The fact that he stopped to block makes it look pretty stupid.
It's hard to tell if the cut from Nightwing saying "It's impossible." to Damian swimming out to the oil rig is meant to be played for laughs or not.
They Wasted a Perfectly Good Plot: Batman and Deathstroke get very little interaction in the movie even though Deathstroke's plan is basically out of jealousy of him and even in Deathstroke's rant at the end everything he says is pointed towards Bruce and sounds like it'd be better said to him than Damian.