Most of the routes in this game are gotten by favoring one character over another. If you try to pick to do things with, talk to, or make a character happy, that is how you will get 'points' towards their endings.

To get Tsugumi Good Ending, get a lot of Tsugumi points and pick 'I'm sorry.'
To get Sora Good Ending, get a lot of Sora points and pick 'I'm so glad you're safe.' The 'Why goddesses?' option will give you more dialogue
To get Takeshi Bad Ending, minimize point gain (if you must get points, pick Tsugumi)

To get You Good Ending, get a lot of You Points and solve the printout first try
To get You Bad Ending, get a lot of You Points then fail to solve the printout
To get Sara Good Ending, get a lot of Sara points and then choose 'The Qualle'
To get Sara Bad Ending, get a lot of Sara points and then choose 'The Lemurian Ruins'

To get to Coco Route from Takeshi Side, choose the following:
1. 'Did you hear something just now?'
2. 'Is she really just sleepy?'
3. 'Why did I feel sad back there?'
4. 'Try it'
5. 'I'm curious.'

1. 'Ask You about the second voice.' -> 'Really?'
2. '8'
3. Lead her out of the room.'
4. 'Shouldn't we all go together?'
5. 'Try it'

After completing Coco Route, you can access BW Route from the Extras Menu