Telling the time in German has a famous trap: halb vier means 3:30, not 4:30, because German counts the half hour toward the next hour. In each round you see a clock face (at B1, a digital time) and choose the usual German way to say it from four options. After every answer a short note explains the rule behind it.
A1 covers whole hours, half hours and quarter hours; A2 adds five-minute steps such as fünf vor halb; B1 practices the official 24-hour time used for trains and appointments, for example dreizehn Uhr fünfundvierzig. There is also a mixed level. A round has up to 10 questions, and you have 3 lives. The game is free, needs no account and keeps your progress in your browser.