Dragon's Lair II marks the only time Dirk actually speaks in the games. Near the end of it, he says "D-Daphne? Yahoo!"
A level was storyboarded but never completed where Dirk was on a pirate ship. Because of the lapse in production, the model ship required for filming the scene was lost by the time filming of it would've taken place. Without the ship the scene couldn't be done and the level was skipped. However the storyboards for the sequence found itself in a few books and in the Blu-Ray.
70% of the animation for the game was done shortly after the release of Space Ace, however by this point the bottom had fallen out of the arcade market, and the funding for the project fell out. It wasn't until five years later that animation on the game was finally completed.
The time machine was deliberately designed to resemble the one seen in the movie of the same name, and it even has a socket into which Dirk inserts his sword to form a lever that activates the machine.