Taxi Challenge Berlin is very similar in concept to Crazy Taxi. The
gameplay is nearly identical, except that in Taxi Challenge Berlin you must
play 21 missions before getting the 3/5/10 minute runs.

You are a taxi driver in Berlin, the German capital, and you need to get
money. So you drive around on the (more or less) authentic streets of Berlin,
and when you see a pedestrian with a colored Euro (€) sign above his head, you
can stop next to him and pick him up. He will tell you where he wants to go,
and you drive him there. To get orientation, you have a large arrow which
points in the right direction as well as a (very small) map.