Many people have noticed that during the Flowey fight, each soul is associated with a weapon you find in the game, as if they belonged to the previous humans before you.
What I haven't seen discussed yet is that finishing the Snowball Golf game in different times assigns you a virtue and a flag color. Each of those virtues is highlighted in a color that matches the six souls. By getting a ball in perfectly, it lists all the virtues and then a message in red.
Each color also coincides with a certain gameplay style.
LIGHT BLUE
Toy Knife + Ribbon
Virtue: PATIENCE
"'Ball.' is 'Small.'. You waited, still, for this opportunity... Then dethroned 'Ball' with a sharp attack."
Cyan bullets are dodged by standing still
ORANGE
Glove + Bandanna
Virtue: BRAVERY
"You are the kind of person who rushes fists-first through all obstacles."
Orange bullets are dodged by moving into them
BLUE
Ballet Shoes + Tutu
Virtue: INTEGRITY
"Hopping and twirling, your original style pulled you through."
When your heart is blue, bullets are dodged by jumping around
VIOLET
Notebook + Glasses
Virtue: PERSEVERANCE
"Even when you felt trapped, you took notes and achieved the end of 'Ball.'"
You are "trapped" during Muffet's battle. The battle involves patterns and switching line-to-line like a notebook. The sans fight also has a purple status effect, which relies on perseverance and memorization to beat.
GREEN
Frying Pan + Apron
Virtue: KINDNESS
"Your concern and care led you to a delicious victory."
Green bullets are good for you. You have to be nice to the monsters and get close to them to activate them. When your heart is green you're in close-combat with Undyne and have to embrace for her attacks
YELLOW
Gun + Cowboy Hat
Virtue: Justice
"Your sure-fire accuracy put an end to the mayhem of 'Ball.'"
Your yellow heart literally fires shots, allowing you to exact justice on Mettaton
RED
Frisk: Stick + Bandage // Original Fallen Child: Real Knife + Heart Locket
...That's you.
Determination. Not actually listed as a virtue, but you get it.
"Try as you might, you continue to be yourself.