Here's the timeline I collated (spoiler alert):
March 17th, 1985 14:42 Honolulu, Hawaii - Act 3, Scene 9, "Ambush" - Beard and Jacket have their photo taken by Evan Wright (the writer), who is a war correspondent at this point. It is shown here that the US is in a war with Russia. The Ghost Wolves (an elite military unit including Jacket, and Beard as lieutenant) then attack a Russian army camp.
October 25th, 1985 08:50 Hawaii County, Hawaii - Act 4, Scene 14, "Stronghold" - The Ghost Wolves' Colonel mention that he is being promoted to Lieutenant-General. The Ghost Wolves attack another Russian army camp.
October 30th, 1985 02:16 Hawaii County, Hawaii - Act 4, Scene 16, "Casualties" - The Colonel gets drunk and dons a bloody panther mask with the 50 Blessings logo. The next morning, he mentions that the US is losing the war. He sends the Ghost Wolves on their last mission, a "suicide mission" to attack a power plant. The mission goes awry and Beard saves Jacket.
April 3rd, 1986 Nukes dropped by Russia on San Francisco. Beard, who is in San Francisco, dies in the explosion shortly after talking to Jacket over the phone.
All events below take place in Miami, Florida except those stated otherwise:
April 2nd, 1989 18:12 Act 5, Scene 17, "First Blood" - Richter (rat mask) gets coerced by 50 Blessings into killing members of the Russian mob for the first time.
April 3rd, 1989 Hotline Miami 1: Jacket gets his first mission from 50 Blessings
April 10th, 1989 19:32 Act 5, Scene 18, "Demolition", until April 23rd, 1989 17:25 Scene 19, "House Call' - Richter doing more work killing Russian mobsters for 50 Blessings
April 25th, 1989 20:18 Act 1, Scene 3, "Hard News" - Jake (snake mask) killing Russian mobsters, under instructions from 50 Blessings
May 13th-24th, 1989 Hotline Miami 1: Events in Biker's point of view (not canon as per events in Hotline Miami 2)
June 3rd, 1989 19:32 Act 4, Scene 15, "Withrawal" - Jake visits the office of a nationalist organization that he has joined (hinted to be 50 Blessings). He then unknowingly does his last mission for 50 Blessings as he gets killed by Russian mobsters (his dead body and mask can be seen in Hotline Miami 1, Chapter 10, "Hot and Heavy").
Alternative timeline (don't get killed in the last floor): Jake does not get killed by Russian mobsters, but gets killed later by a 50 Blessings operative. If Jake collects a floppy disk before he dies, in the next scene, Manny Pardo will allow Evan Wright to collect said floppy disk in the police station. This unlocks the level: Bonus Content, "The Abyss".
June 8th, 1989 Hotline Miami 1: Jacket gets a mission to deal with Biker at the PhoneHom office. He severely injures Biker (shown to still be alive, and scarred in Act 4, Scene 13, "Subway").1 Afterwards, Richter kills Jacket's girlfriend and then shoots Jacket, sending him into a coma, where he dreams of the events of the last few months. He also dreams that Beard is a clerk at various establishments he visits, with Beard saying similar things to their last conversation.
July 21st, 1989 Hotline Miami 1: Jacket wakes up in a hospital and then escapes. He goes home, suits up, attacks a police station and talks to Richter, who is in jail.
July 23rd, 1989 Hotline Miami 1: After finding information in the police station about what he believes to be the source of the phone calls, Jacket then kills the Russian mob boss (the Son's father). Jacket throws away what is hinted to be the picture of him and Beard taken by Evan in Hawaii. Jacket gets arrested afterwards.
July 20th, 1990 13:15 Act 5, Scene 20, "Release" - Richter gets visited in prison by the 50 Blessings' janitors, who are claiming to be "tying up some loose ends." Richter gets led by the police into the prison yard seemingly to be killed. He kills his attacker. A riot happens afterwards. Richter dons a police uniform and escapes the prison during the chaos. He eventually goes to Hawaii.
October 25th, 1991 19:41 Act 1, Scene 2, "Homicide" - Manny Pardo (the detective) killing hostile people in a department store. He visits a crime scene (the "Miami Mutilator") afterwards.
October 31st, 1991 23:47 Act 1, Scene 1, "Down Under" - The Fans (zebra, tiger, bear and two swan masks) commit a killing spree.
November 5th, 1991 16:56 Act 2, Scene 5, "First Trial" - Jacket's trial; Evan (the writer) is in attendance, doing research on Jacket, the "Mask Maniac". He calls Manny Pardo, who is his friend, to ask if Manny knows someone connected to the Russian mob to interview. Evan then proceeds to a mob-owned restaurant, encountering hostile Russian mobsters along the way, to interview this man.
November 11th, 1991 15:37 Act 4, Scene 13, "Subway" - Evan encounters thugs in a subway, interviews Biker in a bar (he claimed to have went into hiding in the desert)1, and meets with Richter's mother to ask about Richter. Some time later, Richter calls Evan. Richter agrees to an interview in exchange for a flight ticket to Hawaii for his mother. Richter narrates to Evan the events of his involvement with 50 Blessings.
November 18th, 1991 21:24 Act 6, Scene 21, "Seizure" - The Son, who is the current Russian mob boss, attacks a strip club run by the Colombian mob.
November 21st, 1991 21:13 Act 2, Scene 7, "No Mercy" - The Henchman wants out of the Russian mob. The Son allows him to leave but asks him to do one last job - to attack a chop shop protected by the Colombian mob. He does so and gets a bag full of cash in the chop shop, and brings it home. The next day he finds out that the cash was stolen by his girlfriend (Mary), who has left him.
November 22nd, 1991 21:13 Act 2, Scene 8, "Execution" - The Fans attack a nightclub. They find the Henchman going mad or hallucinating in there and execute him. They take his phone.
December 2nd, 1991 22:11 Act 2, Scene 6, "Moving Up" - The Fans attack a building full of "low-lifes and junkies".
December 7th, 1991 13:27 Act 6, Scene 22, "Blood Money" - The Son robs a bank controlled by the Colombian mob.
December 9th, 1991 22:05 Act 3, Scene 10, "Into the Pit" - The Fans discuss news about them shown by a news station the previous night. They discuss that they would have to "off more people" to have the news station run another story about them. They decide to attack "creeps and assholes" in a building, and in the sewers underneath, to take their weed stash.
December 10th, 1991 10:08 Act 3, Scene 11, "Dead Ahead" - Manny Pardo goes to Alex Davis' (swan mask # 1) house looking for Ash Davis (swan mask # 2). Afterwards, Manny Pardo proceeds to killing Colombian mobsters on a ship, and then visiting another of the Miami Mutilator's crime scene.
December 14th, 1991 18:12 Act 6, Scene 24, "Take Over" - Manny Pardo visits the Russian mob headquarters, asking to see their boss (the Son). He is refused. The Son attacks and then takes over the Colombian mob's headquarters
December 20th, 1991 21:29 Act 3, Scene 12, "Death Wish" - After getting a phone call on the Henchman's phone from the Son, the Fans attack the Son's headquarters. They all end up getting killed by the Son, except Tony (tiger mask) who is killed by Manny Pardo, despite attempting to surrender to the police.
December 20th, 1991 21:34 Feature Film, "Apocalypse" - After calling the Henchman's phone, the Son, in a drug-induced frenzy, kills many of the Russian mob and the Fans who are attacking the building. He then jumps from the roof of the building and dies.
December 28th, 1991 Richter and his mother watching TV in Hawaii. The TV show cuts to a news report that says the US and Russian presidents were assassinated by armed men, in what appeared to be a coup d'etat led by a US Army General during the Russo-American Coalition conference. Nukes are dropped by Russia on Miami and Hawaii, in retaliation. Those shown killed in the explosion are: Richter and his mother (in Hawaii), Evan Wright (in his home, and with his family, depending on your actions on a previous level), Manny Pardo (barricaded in his apartment), the woman who appears to be Martin Brown's co-actor, and lastly, Jacket (in his prison cell).
Events with no dates and places mentioned:
Pilot, "Midnight Animal" - Martin Brown (pig mask), acts as the "Pig Butcher" in a scene for "Midnight Animal", a film based on Jacket's exploits.
Act 1, Scene 4, "Final Cut" - Martin Brown getting interviewed in a talk show. This appears to be the same interview that Richter and his mother were watching before it gets cut. Martin Brown starts hallucinating talking to Richard (chicken mask). Scene changes to Martin Brown either acting out a scene for "Midnight Animal" or hallucinating that he murders police officers in a police station, and ends up being shot multiple times and killed (unclear if intentional) by the woman he believes to be his girlfriend.
Act 6, Scene 23, "Caught" - Manny Pardo, in a fit of paranoia, hallucinates that he is in a movie where the police are out to arrest him due to them finding out that he is the "Miami Mutilator" serial killer. He hallucinates that he is killed by the police. When he snaps to reality, he gets a call from the police station that there is a situation and he is needed ASAP. He doesn't go and "takes the day off."
Bonus Content, "The Abyss" - In an alternate timeline where Jake gets killed by a 50 Blessings operative, instead of Russian mobsters (Act 4, Scene 15, "Withrawal"), Evan Wright will check out the address listed in the floppy disk's files. It turns out to be a bomb shelter where masked men wearing various 50 Blessings animal masks (one of them is the "Richard" chicken mask) and other thugs stay in.
1 "The Bar of Broken Heroes" is probably an alternate timeline or some sort of limbo, due to the presence of already dead characters in the bar (e.g. Jake and the homeless man killed in HM1). A lot of the game's prominent characters are also present in the bar while Evan and Biker are there.