History AdaptationalBadass / BlackMesa

* Bullsquids, despite their larger size, are now much quieter, and typically the last thing you'll hear before one comes out of cover and starts attacking you is the sound of it inhaling to fire a glob of toxic bile. You won't hear their iconic screaming in this game. They also spit a ''shower'' of acidic puke each time, instead of easily avoided projectiles like in the original ''Half-Life''.

* '''The Hazardous Environment Combat Unit.''' They were already a dangerous threat in the original game, with their CavalryBetrayal in "We've Got Hostiles" marking an increase in difficulty, but here, they go from GoddamnedBats to DemonicSpiders. To wit:

* Xen Aircrafts in the original never demonstrated the ability to attack ground targets, being exclusively an air-to-air combat aircraft. Here? Not only they can engage HECU fighter jets in a dogfight, but they are now capable of attacking ground based targets as seen in "Surface Tension" where they vaporize an MBT (alongside any unlucky HECU marines in the line of fire).

** The grunts weren't pushovers in the original game, but now they do more damage, are much more accurate, and can take more punishment before going down. They aren't afraid to outright bum-rush you while soaking up your return fire. The 1.0 release gave them a considerable boost in intelligence; they now flank you, throw grenades more often to flush you out of cover, and even use suppressing fire on your last known position. Furthermore, they now have {{Combat Medic}}s in the form of the Navy Hospital Corpsmen[[note]]originally only appearing in ''Opposing Force''[[/note]], who are no longer relegated to the [[RangedEmergencyWeapon Glock]]. They wield [=MP5s=] - and occasionally shotguns - with the same deadly accuracy as their comrades. Lastly, there are now considerably more HECU soldiers who pack shotguns, and a few of them even have ''RPG launchers!''

* '''The Hazardous Environment Combat Unit.''' They were already a dangerous threat in the original game, with their CavalryBetrayal in "We've Got Hostiles" marking a serious DifficultySpike, but here, they go from GoddamnedBats to DemonicSpiders. To wit:

* From a story perspective, the Xen aliens in general pose a much clearer threat to the military than in the original. While both versions have the military ultimately back off from the facility due to being overrun, it's ''shown'' far more often in ''Black Mesa''--areas that once had few aliens now have more, and there are many setpieces that show grunts being completely overwhelmed by aliens.

** The Black Ops Assassins are much, much more agile and accurate than their ''Half-Life'' iterations, and now [[GunsAkimbo wield two silenced pistols]] instead of having only one. They can't throw grenades anymore, but suffice to say they don't need to.

* Vortigaunts/Alien Slaves. It was all too easy to completely avoid their attacks in in ''Half-Life'', but here, they fight almost exactly like their deadlier ''VideoGame/HalfLife2'' iterations. They can take more hits, and had their attack speed increased significantly. In general, they fight almost exactly like their ''Half-Life 2'' iterations, which makes them ''far'' more deadly. They also gain said iteration's shockwave attack from ''Episode Two'', allowing them to push you away if you are close to them, and new to this game is their ability to weave to evade your attacks. Just like in ''Half-Life'', they ambush you frequently by teleporting in, which is effective due to their fast attack time and accuracy. You'll be facing large groups of them at a time, especially in "Lambda Core".

** Apaches have adopted many traits of the Combine Hunter-Chopper, including increased durability and ''immunity to small-arms fire''[[labelnote:Explanation]]In Half-Life, the Apache would register damage from any weapon, regardless of type. In Black Mesa, the Apache is impervious to everything besides explosives, the Tau Cannon, Gluon Gun, and the .50 calibre machine gun.[[/labelnote]]. Originally, their low health meant they could be destroyed with a single rocket. Here, they can take up to at least a ''dozen'' rockets before going down [[note]]It's actually much more effective to hit them twice with fully-charged Tau Cannon shots, but [[TooAwesomeToUse ammunition for the Tau Cannon is much rarer]] than the infinite rockets you receive when fighting the helicopter.[[/note]] On top of that, their attack pattern has been revamped; while both their chain gun and missile attacks are telegraphed by distinctive noises (with the former only being fired in Hunter-Chopper-style bursts as opposed to full-auto whenever the player was in the Apache's line-of-sight), sufficiently damaging an Apache will cause it to release a full-on ''[[DesperationAttack missile barrage]]'', once again mirroring the Hunter-Chopper and it's mine spam.

* Houndeyes. They didn't pose much of a threat in the original game, but if you're not careful here, they'll ''mess you up''. Their shockwaves do more damage, charge up in less than a second, and [[InterfaceScrew blur your screen a little while a ringing noise fills your ears]]. [[spoiler:This goes double for their variants in Xen. The little fireball ones will [[MadeOfExplodium explode]] if you so much as sneeze on them, and the knockback ones are ''huge'' and ''will'' send you flying. The first thing you see the latter one do, even, is ''[[EstablishingCharacterMoment throw down with a bullsquid]]''.]]
* Vortigaunts/Alien Slaves. It was all too easy to completely avoid their attacks in in ''Half-Life'', but here, they fight almost exactly like their deadlier ''VideoGame/HalfLife2'' iterations. They can take more hits, and had their attack speed increased significantly. In general, they fight almost exactly like their ''Half-Life 2'' iterations, which makes them ''far'' more deadly. They also gain said iteration's shockwave attack from ''Episode 2'', allowing them to push you away if you are close to them, and new to this game is their ability to weave to evade your attacks. Just like in ''Half-Life'', they ambush you frequently by teleporting in, which is effective due to their fast attack time and accuracy. You'll be facing large groups of them at a time, especially in "Lambda Core".

** The Black Ops Assassins are much, much more agile and accurate than their ''Half-Life'' iterations, and now [[GunsAkimbo wield two silenced pistols]] instead of having only one. They can't throw grenades anymore, but trust us when they say they don't need to.

* While Alien Grunts initially appear to get a case of AdaptationalWimp, [[spoiler:the ones fought on Xen are ''far'' more dangerous than in the original game, as not only are they ''significantly'' faster than they were in the original, they can now hop between platforms and will fire off their hivehands like crazy]].
* Controllers were never a pushover to start with; they were highly mobile, attacked in numbers and had powerful attacks, thus earning many players' hatred in the original game. The devs of ''Black Mesa'' took this a bunch of steps further: not only are they much more numerous and their attacks even ''stronger'', but they can force the otherwise-peaceful Vortigaunts to attack ''and'' they have the ability to [[MindOverMatter throw physics objects at the player]], including explosives. In later stages, they even get smaller versions of their master's invulnerable DeflectorShields. This, combined with the much more evident cruelty they display towards their Vortigaunt slaves, makes them veritable {{Hate Sink}}s.

* Vortigaunts/Alien Slaves. It was all too easy to completely avoid their attacks in in ''Half-Life'', but here, they fight almost exactly like their deadlier ''VideoGame/HalfLife2'' iterations. They can take more hits, and had their attack speed increased significantly. In general, they fight almost exactly like their ''Half-Life 2'' iterations, which makes them ''far'' more deadly. They also gain said iteration's shockwave attack, allowing them to push you away if you are close to them, and new to this game is their ability to weave to evade your attacks. Just like in ''Half-Life'', they ambush you frequently by teleporting in, which is effective due to their fast attack time and accuracy. You'll be facing large groups of them at a time, especially in "Lambda Core".

* From a story perspective, the Xen aliens in general pose a much clearer threat to the military than in the original. While both versions have the military ultimately back off from the facility due to being overrun, it's ''shown'' far more often in ''Black Mesa''.

* '''The Hazardous Environment COmbat Unit.''' They were already a dangerous threat in the original game, with their CavalryBetrayal in "We've Got Hostiles" marking a serious DifficultySpike, but here, they go from GoddamnedBats to DemonicSpiders. To wit:

* '''The HECU.''' They were already a dangerous threat in the original game, with their CavalryBetrayal in "We've Got Hostiles" marking a serious DifficultySpike, but here, they go from GoddamnedBats to DemonicSpiders. To wit:
** The grunts weren't pushovers in the original game, but now they do more damage, are much more accurate, and can take more punishment before going down. They aren't afraid to outright bum-rush you while soaking up your return fire. The 1.0 release gave them a considerable boost in intelligence; they now flank you, throw grenades more often to flush you out of cover and even use suppressing fire on your last known position. Furthermore, they now have {{Combat Medic}}s in the form of the Corpsmen[[note]]originally only appearing in ''Opposing Force''[[/note]], who are no longer relegated to the [[RangedEmergencyWeapon Glock]]. They wield [=MP5s=] - and occasionally shotguns - with the same deadly accuracy as their comrades. Lastly, there are now considerably more HECU soldiers who pack shotguns, and a few of them even have ''RPG launchers!''
** HECU Apaches have adopted many traits of the Combine Hunter-Chopper, including increased durability and ''immunity to small-arms fire''[[labelnote:Explanation]]In Half-Life, the Apache would register damage from any weapon, regardless of type. In Black Mesa, the Apache is impervious to everything besides explosives, the Tau Cannon, Gluon Gun, and the .50 calibre machine gun.[[/labelnote]]. Originally, their low health meant they could be destroyed with a single rocket. Here, they can take up to at least a ''dozen'' rockets before going down [[note]]It's actually much more effective to hit them twice with fully-charged Tau Cannon shots, but [[TooAwesomeToUse ammunition for the Tau Cannon is much rarer]] than the infinite rockets you receive when fighting the helicopter.[[/note]] On top of that, their attack pattern has been revamped; while both their chain gun and missile attacks are telegraphed by distinctive noises (with the former only being fired in Hunter-Chopper-style bursts as opposed to full-auto whenever the player was in the Apache's line-of-sight), sufficiently damaging an Apache will cause it to release a full-on ''[[DesperationAttack missile barrage]]'', once again mirroring the Hunter-Chopper and it's mine spam.

''Black Mesa'' ramped up the difficulty of ''VideoGame/HalfLife1'', to the point you could go back to the original game and feel their hardest levels are ''easy'' in comparison. Likewise, the [=NPCs=] gained a brain and can now assist you properly in battle, [[VideoGameCaringPotential provided you take care of them as much, too]]. [[AdaptationalBadass Take a look!]]

* Houndeyes. They didn't pose much of a threat in ''Half-Life'', but if you're not careful here, they'll ''mess you up''. [[spoiler:This goes double for their variants in Xen; the little fireball ones which [[MadeOfExplodium explode]] if you so much as sneeze on them, and the knockback ones which are ''huge'' and ''will'' send you flying. The first thing you see the latter one do, even, is ''[[EstablishingCharacterMoment throw down with a bullsquid.]]]]''
* Vortigaunts/Alien Slaves. They can take more hits, and had their attack speed increased significantly (it was all too easy to completely avoid their attacks in ''Half-Life''). In general, they fight almost exactly like their ''Half-Life 2'' iterations, which makes them ''far'' more deadly. They also gain said iteration's shockwave attack, allowing them to push you away if you are close to them, and new to this game is their ability to weave to evade your attacks. Just like in ''Half-Life'', they ambush you frequently by teleporting in, which is effective due to their fast attack time and accuracy. You'll be facing large groups of them at a time, especially in "Lambda Core".

* The Gargantuas weren't immune to ''explosive'' weapons in the first game, but the mod now grants them invincibility to all attacks outside of scripted events.
* '''The HECU.''' To wit:
** The grunts weren't pushovers in the original game, but now they do more damage, are much more accurate, and can take more punishment before going down. They aren't afraid to outright bum-rush you while soaking up your return fire. The 1.0 release gave them a considerable boost in intelligence; they now flank you, throw grenades more often to flush you out of cover and even use suppressing fire on your last known position. Corpsmen[[note]]originally only appearing in ''Opposing Force''[[/note]] have joined the party, and are no longer relegated to the [[RangedEmergencyWeapon Glock]]. They wield [=MP5s=] - and occasionally shotguns - with the same deadly accuracy as their comrades. Lastly, there are now considerably more HECU soldiers who pack shotguns, and a few of them even have ''RPG launchers!''
** HECU Apaches have adopted many traits of the Combine Hunter-Chopper, including increased durability and ''immunity to small-arms fire''[[labelnote:Explanation]]In Half-Life, the Apache would register damage from any weapon, regardless of type. In Black Mesa, the Apache is impervious to everything besides explosives, the Tau Cannon, Gluon Gun, and the .50 calibre machine gun.[[/labelnote]]. Originally, their low health meant they could be destroyed with a single rocket. Here, they can take up to at least a ''dozen'' rockets before going down [[note]]It's actually much more effective to hit them twice with fully-charged Tau Cannon shots, but ammunition for the Tau Cannon is much rarer than the infinite rockets you receive when fighting the helicopter.[[/note]] On top of that, their attack pattern has been revamped; while both their chain gun and missile attacks are telegraphed by distinctive noises (with the former only being fired in Hunter-Chopper-style bursts as opposed to full-auto whenever the player was in the Apache's line-of-sight), sufficiently damaging an Apache will cause it to release a full-on ''[[DesperationAttack missile barrage]]'', once again mirroring the Hunter-Chopper and it's mine spam.

* While Alien Grunts initially appear to get a case of AdaptationalWimp, the ones fought on Xen are ''far'' more dangerous than in the original game, as not only are they ''significantly'' faster than they were in the original, they can now hop between platforms and will fire off their hivehands like crazy.

''Black Mesa'' ramped up the difficulty of ''VideoGame/HalfLife1'', to the point you could go back to the original game and feel their hardest levels are ''easy'' in comparison. Likewise, the NPCs gained a brain and can now assist you properly in battle, [[VideoGameCaringPotential provided you take care of them as much, too]]. [[AdaptationalBadass Take a look!]]