Here is the full list of all 15 Beach Pong achievements.
Win "No timer" mode game
Win "15 goal" mode game
Win "1 minute" mode game
Win "2 minutes" mode game
Win "5 goal" mode game
Win "3 minutes" mode game
Win "4 minutes" mode game
Win "10 goal" mode game
Win "Hard" mode game
Win "Medium" mode game
Win "5 minutes" mode game
Win "20 goal" mode game
Win "6 minutes" mode game
Win "25 goal" mode game
Win "Easy" mode game