Humanism & Electronic Commerce Systems Engineer/Programmer interview questions

I was contacted by a recruiter who asked for work samples of apps I have worked on in the past. I sent him a PDF portfolio. Soon after, he set up an in person interview, and instructed me to print out a physical copy of my portfolio. I was interviewed by two people at once. The recruiter advised formal attire, but the interviewers arrived in jeans and t-shirts and the interview itself was a bit more casual than I had been expecting. They were fine with me showing them an app I had created on my own phone, and at one point whipped out a tablet to look up projects I had worked on.