Timeline

The Original Universe
The story begins in the Original Universe, in which Needlemouse, Miles, Tiara, Terios, Venice and more lived in relative peace. The Original Universe's residents don't often talk about their pasts, so a lot of information comes from the video games created about the events of their lives. The current documented timeline is as follows:

Pre-Mr. Needlemouse
Needlemouse, as a small child, was wandering through a rainy forest; he was a regular brown hedgehog when he was found by Doctor Kintobor, who took him in. Needlemouse named himself by looking at a mouse-shaped pincushion in Kintobor's lab, thinking it looked like him.

Some time later, Kintobor asked for Needlemouse's help with an experiment which would involve Needlemouse running on a treadmill. Something went wrong, however, when Needlemouse's speed sent the machine into overdrive; causing it to explode and turn his fur, blood and insides blue. This story is near enough identical to Sonic's backstory in Sonic the Comic, although Kintobor was remarkably different; sporting pajamas near constantly.

Mr Needlemouse
Not much is known about this period of time, other than that there is a video game explaining it's events. So far the game has not showed up. It can be assumed that some kind of evil force or individual was threatening Needlemouse's world, so he went on some kind of adventure to stop them.

Pre Mr Needlemouse 2
Needlemouse enjoyed peace once again, and one day met Miles, who was adopted by Kintobor as Needlemouse's little brother.

Mr Needlemouse 2
While the game detailing this time period has been played, there were little to no details offered.

Needlemouse X-Treme
Needlemouse received a message from someone called 'Saturn', who was asking desperately for help in her world, 'Micro Mobius'. Micro Mobius is a virtual world created long ago by one of Kintobor's ancestors, and was left alone to avoid playing god. Needlemouse asks Kintobor to be sent into Micro Mobius, Miles staying behind to take care of Needlemouse's body while he is away. Miles acted as support throughout the adventure, in which Needlemouse made his way through the Zones of Micro Mobius, meeting up with Tiara, who was also looking for 'Saturn'. The two of them fought together through hordes of monsters until they conquered the Final Flagship Zone, riding a rocketship off of the Zone to Saturn, where she revealed herself to be Queen Saturn, mother of Tiara. Tiara was delighted to have found her mother, but the Queen soon showed off her true colours as she attempted to kill Needlemouse and Tiara due a prediction she had seen stating that one day, the two of them would be her downfall. She was seemingly defeated, but the victory was hollow.

Post Needlemouse X-Treme
Tiara and Needlemouse had grown quite close during their adventure, and due to events near the end of said adventure, Tiara had little place to go. She opted to stay connected to Needlemouse through a pair of twin handhelds, and after a while of working she left Micro Mobius completely to help out around Kintobor's lab as an A.I that could appear in Kintobor's interfaces or Needlemouse's handheld.

Needlemouse X-Treme 2
The only event known about this timeline, confirmed by SinFrog, is that Tiara gained a physical body at some point.

???
An undisclosed amount of time later, Terios appeared and was an enemy to Needlemouse. Eventually, however, Needlemouse turned him over to the side of good; Kintobor allowed him to stay in his laboratory, where he would assist the scientist with his knowledge of Chaos Energy and enhanced strength.

???
Between this and Prototype Terios, Venice and Flare make themselves known.

Prototype Terios
More time passes, Terios meets a 'hologram lady' who tried to convince him to work for her. Terios went to South Island, and in the game was offered a choice between attacking Needlemouse or fighting off the 'mysterious creatures' invading the island. Because of the choice based nature of the game, it is unknown which choice Terios actually made. Needlemouse's nervous reaction possibly hints that Terios' choice might have been less than savoury...

???
There is a large stretch of time where nothing is known, this could be an incentive to get playing. The only thing that can be roughly placed somewhere in this time period is the video on Terios' computer showing himself, Needlemouse, Venice and Tiara playing a song together.

The Day of the Original Universe's Death
The fateful day in which Infinite arrived in the Original universe was an innocent one. Needlemouse and his friends were gathered in preparation to go out somewhere, those present being: Needlemouse himself, Miles, Tiara, Terios, Venice and a 'red wolf' that has been mentioned previously in Terios' video. Infinite made his presence known with a flame-based attack that struck suddenly, burning Miles alive and killing him before anyone could even react. Needlemouse attacked him in a fit of rage but was knocked away, leaving the others to hold him off. During the battle Infinite choked the red wolf, seemingly vaporizing him as light filled his body before he vanished. Terios lost an eye during his own duel with Infinite and finally Tiara had her robotic arms crushed at the upper-arms and ripped off. With every one else down and out, Needlemouse got up and attacked Infinite again while Venice was stunned in shock. Infinite, in a move that would create a pattern echoing across the multiverse, impaled Needlemouse through the chest with a beam attack; this would lead to a pattern of Sonics all throughout the multiverse dying via impalement, namely Modern Sonic's death at the hands of Mephiles and Swap Sonic's death at the hands of the Metal Overlord. Venice was the last one left, and fighting through the cacophony of his own emotions he unleashed a powerful attack that almost killed Infinite while destroying his own optic nerves, blinding him. The story gets foggy here, as the video telling The Story turned off at the request of Nova, but we do know that Infinite destroyed the Original Universe, leaving it's residents alone in the endless void. He was unable to retrieve what he was looking for, the Original Phantom Ruby.

The End of Reality..?
For an brief time after the Original Universe's death, few survivors drifted in the void outside of their destroyed universe, namely Needlemouse, Terios, Venice and Tiara were all somewhat close to each-other, with Honey, Madonna, Salve and Turbine and possibly more drifting elsewhere. It was then that the Tiara used the Original Phantom Ruby to enter a kind of transformation (that has not been shown or been namedropped so far,) and round up all the survivors of the Original Universe. After saving everyone she could, she tapped into the Orignal Ruby's power to create a massive surge of dimension-altering Phantom Energy, creating a small universe that would act as shelter for herself and all the survivors. A time later, the survivors awoke and began to build themselves back up from nothing, eager to make use of their second chance.