Here is the full list of all 13 JellyMen achievements.
Played your first ever game of JellyMen
Finished playing 10 games
Die 100 times
Play 50 levels
Play Hot Potato
Play Capture The Flag
Play Race
Play Jelly Fight
Play a game with 4 players
Play an hour of JellyMen is one sitting
Pick up 500 weapons
Get sucked into a blackhole
Pass the hot potato 100 times