SPOILERS AHEAD
I've never been this disappointed over a kdrama. I give 3stars for the main lead's acting, the cgi, the whole scifi theme and effects plus I'm very impressed with their fight scenes which were amazingly choreographed, swift and wonderfully delivered by the actors especially by the lead actor. However I feel that I wasted so much time finishing the show because after such an amazing first half, the plot went downhill and ended badly.
It was weird enough that the mom's past self was developing romantic feelings for her future son but to end it with them together just made it even weirder and super cringy. First off, they were physically not compatible, second she was a lot older than him (calculating their age would probably have at least 6yrs difference) then lastly, she was his mom for crying out loud!
The whole plot was messed up. I don't understand why his old self had to kill his mom, what does that change? He could have just killed himself in the first place if his only purpose was to stop time.
The whole show actually reminds me of the movie Butterfly Effect by Ashton Kutcher. That movie made more sense than the ending of Alice.
Props for the effects and the acting though but storywise, utter disappointment.