Alert to all interviewees of Titan: They withdrew the offer to me because of "structure change" of their company, and thus "I can't fit in their company anymore". They sponsored my O1 visa, I am acting proactively, and everything is on track for me to start working in a month or two. It's quite un-classy to withdraw an offer. Please think twice/three times before you consider accepting their offer. It's a total waste of time. First-round recruiter with experience on the resume Second round with the CTO Third round giving a presentation on site about past research experience and talk with team members for behavioral assessment.