While Shenmue 3 managed to set a video game record on Kickstarter it still fell short of some of the loftier stretch goals. As of yesterday there's a chance for "slacker backers" to join the fun and pledge their support via PayPal on the official website. Most of the various reward tiers are still available, however the Slacker Backer campaign only includes the PS4 version at this point (PC version may be added later on).
A FAQ was provided with some details on the campaign and popular questions, and this was the stated reason for the Slacker Backer campaign:
"This additional campaign comes as a response to all of the requests we have received asking for another opportunity to participate in the making of Shenmue III because either of a lack of payment options on Kickstarter, or just not having a chance to pledge before the campaign ended.
While the full game will be completed as promised with the use of the funding collected on Kickstarter, any additional funding collected here will go towards reaching the Stretch Goals to make the game even bigger and deeper."