Here is the full list of all 13 Proficient Paddles achievements.
Played the game for the first time.
Chosen a non-default paddle. (Standard Paddle Theme)
Won your first game (Single Player Only)
Viewed the names of the people that have been here from the beginning or near the very end.
Played two player for the first time.
Won a total of 5 games
Won a total of 10 games
Won a total of 15 games
Won a total of 20 games
Won a total of 25 games
You selected a country paddle, now you're truly ready to represent!
Lose a game for the first time. (One Player Only!)
Started a game with a country paddle equipped on both players (Two Player Only)