Since I am heavy sleeper I have tried many alarm applications. This one has it all for me. It has multiple alarms, countdown alarms that wakes you with song or sound you choose, volume you choose. You can select dismiss challenges to solve to prevent oversleeping (Captcha, WiFi, math problems, Qr code) whatever you choose. For me math is most effective. 

You can restrict alarm to certain locations. Off days can be selected for alarms won't go off.  Alarm App when alarm is activated notifies you with recommendation to go to sleep. Best thing of all there is fantastic option to turn on! After you turn off alarm completely after couple minutes notification with sound of sms is shown to ask if you are awake. If you fail to answer during configured time period then the alarm will go of again.