Heartbeat:I have never read 'Toki Doki', so I can't really make a comparison based on that.
But why did you have to trick me?

I was going along believing that Mayuyu was fulfilling Yukirin's dreams, then it hit me like a train.

First Mayuyu, then Yukirin.

Overall, I liked how you made short scenes showing the progression of the characters.
Bestfriend:I enjoyed this one.
I laughed when Mayuyu was carrying 2 buckets of ice cream to Yukirin's house.

The part I found the most adorable was when Mayuyu took a train to Nagoya to see Yukirin.

But the best part was when they said "I love you." to each other.
General:I think your writing is good.
It has its own style, which is good.