This is a summary of the events of Entropy Zero 2 original Half-life 2 Episodes. It contains a lot of personal understandings and guessing. Feel free to correct me or add more details.
 
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The event preceding EZ2

 
1. Advisor sent Clone 36 and a Recon team to Arbeit Facility.
 
 
2. Mossman boarded immediately a chopper from Black Mesa East, flew to ArbeitComms, after saving Eli and Gordon. After arriving, she did her researches on the subject and recorded everything.
 
 
It is uncertain which of these events occurs first. Timeline wise, the clone might have been down in the Arbeit/Aperture Facility for a while so we can a*sume Evil 36's primary goal is to reconfigure Work Comms, not to track down Mossman.
 
 
 

The Journey, the Awakening.

 
3. Clone team failed while Mossman managed to escape, both of which combined led to the Advisor activating Main 36.
 
 
Between event 1 & 3, Citadel teleporter Blew Up
 
 
4. Gordon was buried, while 36 were subject to Aperture Testing and Exhumation. Mossman arrives in Arbeit 2 to send her research for the C17 rebels.
 
 
According to Episode 1's Emails and the original Half-life 2 development team, Gordon was buried for only one or two days before Alyx discovers him. Walker can travel through all these areas in enough time to reach Arbeit 2 (.
 
 
5. 36 failed to capture Mossman from Arbeit 2 facility. Mossman fled and transmission was interupted and intercepted the Advisor. This information ends up in C17 citadel’s Database.
 
 
6. Gordon was found and watched by Alyx while 36 made his way towards Arbeit 3 and went after Mossman.
 
 
 

The Final Countdown

7. 36 entered Entropic Control, defeated the clone, and Gordon and Alyx attempted to escape C17
 
 
8. 36 were able to survive Entropic Lift Control to anomaly. Gordon and Alyx saw the Ruins of Citadel create a Portal Storm. The Portal Storm spread to Entropic Lift Control.
 
 
9. Alyx was hurt by a Hunter while fighting with the Advisor. Vortigaunts started hunting Advisors and came to a*sist 36.
 
 
The reason I stated that the Phenomenal took place inside Entropic Lift control was not due to the Anomaly/Borealis but because you are very near the Anomaly but the Portal Storm is nearby You can see your manifests wherever you enter But not from the Lift connecting to the Anomaly. It was therefore not within the Arbeit Anomaly Area.
 
 
 

The Omega

10. 36 meets Gman, Gordon finds Antlion Extract, Vortigaunts start to heal Alyx. Gman then has the opportunity to give up 36 and go talk to Gordon.
 
 
As mentioned in the previous chapter. If the portal storm is manifested by the Citadel, then that will explain why Gman will abandon 36 mid conversation, which also connects these two series.
 
 

Personal Speculation/Explanation:

 
 
The real problem is: Why would G-man bring Aiden back to his Hideout?
 
 
My suspect is on. Do you remember where G-Man takes Gordon after the HL1 events? The tram of Black Mesa is a place Gordon visits often and is familiar with.
 
 
G-Man brings Shepherd with him to the Osprey. He is a HECU soldier and spends a lot training there.
 
 
According to my speculation, G-Man brings 36/Aiden Walker back to his old apartment/ward. Would you like to hire him? Make him a Candidate. Or at least, make him an alternate plan and suspend him. If I am correct, it means G-Man has already lost command of Gordon Freeman. This makes Vortigaunt's theft an event to EZ2.
 
 
Another problem is the fact that 3650 woke up to find the citadel in flames. This means Vorts may have already saved Gordon Freeman from the blast and G-Man's suspension. Combining that with the underground portal storm, I tend to agree with my opinion.
 
 
The final detail that makes it to the end, after the Citadel's total loss, is a minor game mechanic.
 
 
I don’t know if anyone noticed, but the 36 unit summoned using Xen Relay Grenades is no longer Xen creature, but only Vortigaunts. There are many Vortigaunts and they all work without shackle.
 
 
These Vortigaunts are believed to have scrambled Xen Relays, or more accurately, used the borderworld Xen for a jumping platform and ended in helping 3650 fight. These Vorts know what they're doing when they arrive. They immediately start attacking the Advisor and avoid attacking the 36.
 
 
After defeating Advisor, 3650 talk with the Vorts to get their reply: "We will continue hunting for Advisors."
 
 
This line confirms the end of the battle after Citadel's Utter Anihilation. As Vortigaunts have not started hunting for Advisors since they were ejected repeatedly from Citadel's Utter Annihilation.

 
 
This is all for Entropy : Zero 2 Events Guide + SPOILERS hope you enjoy the post. If you believe we forget or we should update the post please let us know via comment, we will try our best to fix how fast is possible! Have a great day!