* AuthorExistenceFailure: DwayneMcDuffie had died partway through the series. Didn't prevent the show's continuation and eventual sequel series, though, and all 52 episodes for ''UA'' had already been fully planned out before his passing.....though, for some reason or other, many plot threads brought up were left completely unresolved by Episode 52 (the ones centering around Elena, Charmcaster, and King Viktor being the most noteworthy) and now likely never will be due to Dwayne's passing.
* CastingGag: Actress Jennifer Nocturne, who wants to get into a relationship with Ben, is voiced by TaraPlatt, the real-life wife of YuriLowenthal.
* CreatorBacklash: If [[http://www.formspring.me/DerrickJWyatt/q/305578315308085773 this formspring]] is to be believed, the person who designed Aggregor is embarrassed about him.
* HeyItsThatVoice: Creator/DeeBradleyBaker uses his [[WesternAnimation/AmericanDad Klaus]] voice for [=ChamAlien=] and Prisoner Number 775.
* TheOtherDarrin: Zombozo is now voiced by {{John DiMaggio}}, rather than John Kassir.
* PlayingAgainstType: As mentioned in TheOtherDarrin, John Dimaggio as Zombozo, in what almost seems like practice for [[WesternAnimation/BatmanUnderTheRedHood another role]].
* RecycledScript: The plot for "Inspector 13" seems fairly similar to the first series episode "Secrets", down to Ben's arm being at the risk of being cut off for his watch.
* TalkingToHimself: Bivalvan, P'andor, Ra'ad, and Andreas are all voiced by Creator/DeeBradleyBaker. Galapagus is the only one not voiced by Baker, and is instead voiced by {{John DiMaggio}}, though it could count when Galapagus talks to Aggregor.
* WordOfGod: Dwayne [=McDuffie=] had [[http://dwaynemcduffie.com.lamphost.net/forums/viewtopic.php?f=2&t=2104 started a new thread]] for ''Ultimate Alien'' and any remaining ''Alien Force'' questions… Up until [[AuthorExistenceFailure he died]], at least.
** Matt Wayne seems to have replaced him, as he was the one who confirmed the death of Pierce in "The Purge."