Bosses

Kevin, The Dark Scientist
Kevin, The Dark Scientist, is an optional boss to face, he has 1500 Health, 60 Damage and 10 Defense, in his first phase he will walk towards the player and attempt to kill them, in second phase he will grab a Ray Gun and shoot at the player, He is very easy to kill at the start of the game, usually the first boss the player will fight, you do not need to kill him to progrees through the game, however killing him will grant you Kevin's Armour that gives you 1500 Health Plus, a speed boost, it is definitely recommended to kill him nevertheless.

Stone Golem
Built By Kevin The Dark Scientist, Stone Golem is another easy-Optional Boss to Face With 2200 Health 90 Damage and 25 Defense, he can be a threat to new players, to kill him, you need to get to the vent on the surface and go through it to find and kill him, he only has one attack: Ramming into you, it will kill you very easily if you do not have any Armour, any Good Weapon will kill him, and avoid using Melee Weapons for this fight, Killing him will Grant you access to Stone Armour, it makes you slower, but gives you 5000 Health.

Plaguebringer
The Plaguebringer is a Massive Boss With 3000 Health 130 Damage and 40 Defense behaving similarly to that of the Stone Golem, who is a hard boss to defeat, he is just like Stone Golem, but does more damage and Defense, to find him, you will need to finish the Acid Parkour, Use weapons like the Ray Gun for most Damage, and avoid slow Armour, and melee Weapons, when you kill him, you will collect the Toxic Armour That gives you 8000 Health and The Toxic Ray, which can help you with the following boss(es), but don't underestimate the Plaguebringer's Power!

Homermafia1 and Portela1
Homermafia1 and Portela1 are a Group of bosses that spawn in the Boss Chamber, Together they have 4000 Health and 1100 Damage and 25 Defense, they are the only Vanilla boss in the game, they, like other bosses, only have the potential to Ram into you, inflicting damage, but they have much more damage than other Bosses, use the Toxic Ray to Kill Them, when you kill both of them, you are rewarded with the Ultra Gun and the Ultra Armour witch gives you 10000 Health, Killing them is the only way to advance through the game.

Supreme-PAMA
Supreme-PAMA is considered the second-hardest Boss in the Game with 7000 Health 2000 Damage and 50 Defense, she is almost has stats double to that of the previous Boss, she is an Upgrade from PAMA and is very strong, she shoots lasers that do 2000 Damage upon hitting the player, she is also very fast, killing her will grant you the Lunar Ray, and Supremus Armourus, which will help with the Following Final Boss, Finally she drops the Temple Key, to enter The Temple, and after you kill her for the first time, most other enemies will get a Boost on all stats, making it harder.

Cataclysm, The Destroyer of Gods
Cataclysm, The Destroyer of Gods is the Final Boss of the Game with 15000 Health, 7000 Damage and 70 Defense, considered a SuperBoss, He is currently the most challenging enemy in the Area 51: The Next Generation and is notoriously difficult, The Player must be equipped with Strong Armour and have Powerful Weapon if they attempt the Challenge him, after you do finally defeat him, you will be rewarded with the True Ultra Gun Of Might and the God's Armour, Protector of Hell,  which gives you 20000 Health, a worthy reward for beating the final Boss in the Whole Game.

Bill Cipher
Bill Cipher is a Large-Triangle Miniboss With 1800 Health, 1300 Damage, and 30 Defense, a Threat to New Players, who have not encountered him yet, To find and kill Bill, you must follow the Bill Markings around the Map, free bill and Kill him. While he seems like a common killer, he is usually found dead, stuck or out the Map, making him rarer than he actually is.

Demon
Demon is a Rare Miniboss that spawns near The Diamond Armour Location.2, He has 300 Health, 1000 Damage and 10 Defense He is a real challenge to New Players, but easily avoided, the player must be well equipped before facing him, as it could lead to an easy death, it's best to kill at least on of the bosses listed above, before trying to face him.

Mr.WellDone
Mr.WellDone is a Mini Boss that Spawns Close to The Spawn on Floor 1, he drops the Sword Congratulations Sword Every Time he dies, with 1500 Health, 1000 Damage and 10 Defense, he is easily killed because of his size, however he does fit through most spaces and can catch most players off guard, and manage to sneak behind them before they get a chance to find it, however it is still a strong boss to encounter.

Toxic King
The Toxic King is a Toxic Mini Boss that spawns in the first cell of The Toxic Prison, It has much more health than the Toxic Warriors, with 200 health, 800 Damage and 6 Defense, it is quite and easy boss to kill for beginners, however because it is quite slow, but usually missed due to people opening the first cell of the Prison.