History YMMV / HalfLife1

* SeinfeldIsUnfunny: The vast majority of the game's innovations have since been copied by every single first person shooter to come since. The game itself has also not aged very well, with the [Narm] factor being the most obvious.

* SeinfeldIsUnfunny: The vast majority of the game's innovations have since been copied by every single first person shooter to come since.

** Near the end of ''Surface Tension,'' you reach a map layout that requires you to find, and escort, a security guard to open a door to the next area. Getting stuck in doors usually does a slight bit of damage to you. However, ''this'' door does the exact opposite and HEALS you instead; to the point that purposefully getting stuck in the door will allow the player to obtain health levels ''beyond'' the 100 health limit. Want 4000+ health? Just get yourself stuck in the doorway.

* FunnyMoment: In the Playstation 2 version of the Hazard Course. "I, Gordon Freeman, hereby agree to the following terms, blahblahblah, in any case of serious injury, dismemberment, toxic poisoning, burns, rashes, blah blah, etc. etc..."

** [[AWizardDidIt Gman did it]].

* UglyCute: The Spore Launcher from ''Opposing Force'' is a repulsive alien creature that Shephard can use as a weapon. But if you hold still for a bit, [[http://youtu.be/J06tqrJt6pE?t=7s Shephard will pet it]] and for a moment it’s just adorable.

* AlternateCharacterInterpretation: Is Gordon just an innocent scientist caught up in a much larger plot and forced to take extreme measures to survive, or did he deliberately cause the Cascade and is trying to escape and cover his tracks?

*** You can climb the cement divider barricade at the start of ''Power Up'' to skip the entire level (While this is ''still'' possible in the Source version of the game, you can no longer squeeze your way through the tram-drop elevator to get to the next area, so you'll need to go back to get the tram working this time around anyway). Also, due to an overlap oversight between the first map sections of ''Power Up'' and ''On a Rail.'' It's possible to glitch the crate items from the ''Power-Up'' area to duplicate into the ''On a Rail'' map for extra health and trip-cameras.

* ThatOneLevel: The Chapter[[FunWithAcronyms Foxtrot Uniform]] in ''Opposing Force''.

* SeinfieldIsUnfunny: The vast majority of the game's innovations have since been copied by every single first person shooter to come since.

*** At the very beginning of ''We've Got Hostiles!'', you can glitch the scientist to open the security door which will allow you click the button to open the silo door to the Blast Pit; effectively skipping the entire chapter.

*** Near the end of ''Office Complex'', you can push a security guard towards a locked exit door to open it from the locked side, allowing the player to skip having to traverse through the Freezer portion of the level.
*** At the very beginning of ''We've Got Hostiles!'', you can make the scientist open the security door through a glitch whici will allow you to open the silo door to the Blast Pit; effectively skipping the entire chapter.

*** Near the end of ''Office Complex'' you can push a security guard towards a locked exit door to open it from the locked side, allowing the player to skip having to traverse through the Freezer portion of the level.

** You can also skip an entire chapter with the door glitch.

** Ichthyosaur. There are generally two strategies for how to fight it - either jump for it into the water and start frantically firing your crossbow while avoding being eaten, or [[http://images2.wikia.nocookie.net/__cb20120805180422/half-life/en/images/5/59/Icht1.png Bug it above your head and kill it with a crowbar.]]

* GenreTurningPoint: For the FirstPersonShooter genre. Prior to Half-Life, First-Person Shooters were generally "shoot everything you see" with no sense of tactics or strategy, and the extent of puzzles were just simple "search for the key and lock" puzzles. Half-Life changed that with more complex enemy A.I., requiring much more care on how you progress.
* GoodBadBugs: Due to game using scripting quite often, scripted behaviour can be heavily abused. Especially useful with one Gargantua - it's spawned neutral and if you remove trigger of chasing script (what can be done with pistol, FYI), it will remain as so. ''This can be done twice in whole game''. Miniboss fight easily averted.
** Ichthyosaur. There are generally two strategies how to fight it - A: Jump for it into the water and start frantically firing your crossbow while avoding being eaten or B: [[http://images2.wikia.nocookie.net/__cb20120805180422/half-life/en/images/5/59/Icht1.png Bug it above your head and kill it with crowbar]]

* DisappointingLastLevel: Xen. Previously known as ''Xen Syndrome'', HalfLife was the founder of this troupe due to its annoyingly designed jump puzzles seen throughout the alien world levels.