manga(s) that left me astonished

The story takes place in Ikebukuro, Tokyo. The main character, Yamato, cares a lot about his younger twin brother, Yuuto, and is unable to confess to Michiru, his childhood friend. One day those three are shocked by a sudden situation... !!!

Aono Hajime was a prodigy violinist until he grew jaded with playing the violin due to personal reasons. Now in his third year of middle school, he struggles to decide his academic path. One day in school, he meets Akine Ritsuko, a hotheaded novice violinist who wants to enroll in a high school with a distinguished orchestra club. When he finds himself getting closer to Ritsuko and being brought back to the world of violinists, time starts moving again for him.

"It" was abandoned alone on the surface. After wandering, "It" finds a boy who lives in an isolated snowscape.

This story depicts a yankee high school student and his aim to be a top voice actor.

Fuji, who can see the "red string of fate" is in an unrequited love with his university classmate, Yuka. However, Fuji is hiding those feelings in his heart.
This is because he knows their "red strings of fate" aren't connected. Do you believe in "fate"?
This is a love story that will make your heart go "kyun", depicting the love of adults being toyed with by fate.

When the licensed detectives can't or won't take a case, it's up to the super sleuths at MOGURI--- Kizuna Kagami and his partner Maya Midou.
Kagami is an empath who can feel the emotions of others. This incredible ability is a mystery unto itself.
The stirring tale of these two outrageous and irrepressible individuals and their eccentric clients begins here!

A short story about a boy whose name is Yutaka and sucessfully sings as a soloist in a choir with his soprano voice, but then gets into the trouble of his puberty vocal change.

Set in Tokyo it's described as a space action series between humans & extraterrestrials.

A tale about a modern deep-sea aquarium employee in Tokyo!

What's living in the overwhelming darkness deep within the sea? Take a glimpse into this strange world about a boy working at a deep sea aquarium.

When a family of three book passage on a luxury liner they soon realize that the glamours cruise ship is nothing but a facade as a series of mysterious killings spread throughtout the ship. With the sea proving no escape, how will they survive?