Standard Samsung alarm pops up and tells you the hours and minutes until it goes off after you set an alarm, it has saved me a few times.
my absolute biggest fear, the sweet release of death and entrance into oblivion is preferable to the horrible fate of what the meme conveys
My favorite is when it switches to p.m. and you don't notice.
I found myself sleeping through alarms most of the time. I am a really heavy sleeper, and they seem to shut off after a while. So I set timers instead. The timer beeps until you shut it off. You can ask google to set a timer for 0530 and it calculates the amount of time and sets a timer for that long. Really useful.