Drop off percentage wise looks comparable to some other high profile projects.
Project Eternity has 10% off its first day pledge on day 5.
Torment: Tides of Numena has 4% of the inital day on day 5.
Mighty No 9 had its first peak on the second day, day 6 was about 19% of that.
Wasteland 2 11% of its inital day on day 5.
Shadowrun returns 13% of inital day on day 5.
Unsung Story had 12% of its inital day on day 5 (day 5=18th so one day after Matsunos tweets). Its pretty much in line with most of those, only Mighty No. 9 had a significantly stronger sustain of pledges. Masunos Tweets were on the 17th, so it's possible that a possible effect might still happen, but so far I don't think you can make a connection between the tweets and the amount of money pledged. The big fall of pledges was on the 16th, the third day of the kickstarter and one day before the comments of Matsuno.
Didn't look up any specific kickstarters, just some of the top of my head, so they might not be representative but I feel that projects that are connected to some well known properties or developers are actually good cases for a comparison.