YMMV / Alien Breed

• Complete Monster: In the reboot trilogy, Walter E. Klein was the Chief Science Officer on his ship, who was obsessed with immortality. Killing his dog Max in the past to learn about death, Klein led the Phoenix Program, where he created the hostile aliens, and then took control over them and unleashed them upon his ship, which led to everyone else on his ship getting killed, including his own wife. Becoming an AI within this ship, thus achieving immortality, Klein remained in space until his ship collided with another ship, the Leopold, at which point Klein had no problems sending his creatures to slaughter everyone on the Leopold. Taking over and mutilating the body of an android Mia, Klein mocked and taunted Joseph Conrad at every opportunity, as he attempted to kill the latter.
• Demonic Spiders: The Security Helicopter Drones in the outdoor levels of The Horror Continues, for once, kill you instantly the moment you happen to be under them. Like, how do these things kill you? Do they fly just at low enough attitude that they would supposedly decapitate you with their rotors like you were Vic Morrow?
• Event-Obscuring Camera: Unlike, say, Alien Swarm, the maps in this game are designed in such a way that you can't always see what you're doing, requiring you to manually rotate the camera view to maintain perspective on the action.
• Hilarious in Hindsight: The series being an influence on Doom to later shift into First-Person Shooter series went full circle when one of said FPS installments were remade on the GZDoom engine as Project Osiris.
• Narm: The CD version of Tower Assault featured a live-action intro sequence, something which wasn't really common at the time of the game's release. However, due to terrible acting — further hampered by poor audio quality which makes part of the dialogue near-unintelligible — it's hard to take it seriously.
• Nightmare Fuel: The Series Mascot is no less intimidating looking than it's inspiration, moreso when The Horror Continues gave it quite a makeover, and the first two games love to put that creature in the title screens (with The Horror Continues reendition looking borderlinge photorealistic for the time). The moody and tense title theme tunes only enhance this.
  • Tower Assault takes a break with feauting that creature on it's title screen (but not on it's boxart where it's still there), but makes up for that in terror with the indoor levels pulling no punches with showing the aftermatch of the carnage the Aliens have done in their wake.
• Nintendo Hard: The 2D games have reputation for being tough, mainly stemming from the never-ending supply of Aliens, having to manage the finite supply of keys, credits and ammunition and a number of self-destruct sequences that put your routing/memorization skills to test.
• Porting Disaster: The PC floppy version of Tower Assault omitted a large number of levels and the non-linear gameplay.
• Spiritual Successor: The first game greatly influenced Doom. Which kinda says something if you consider that the series would later get its own FPS spin-off.
• Updated Re-release Difficulty Drop: Special Edition 92 greatly increases the number of pickups you can find in the levels, has the levels a bit less cramped and nerfs the enemy respawn mechanics.
• Values Dissonance: One of the cheat codes for the original game was "ALIENS ARE FAGGOTS", which caused the aliens to run away from the player. It was openly printed in every magazine that listed the cheat codes. When the game was re-released, the code was changed to the slightly-less-offensive "ALIENS ARE BENDERS".