Definitely casual. The place is a dive. If you care more about delicious food than posh surroundings, you're in luck. Cheap ($7-8) entrees in generous portions. Falafel, stews, curries. Warm, welcoming feeling inside.
They have 3 locations - the one listed, another in Kitsilano and one on Powell Street: http://www.urbanspoon.com/ch/14/15029/vancouver/deserts-the-falafel-oasis