Here is the full list of all 10 Wordament Snap Attack (Android) achievements worth 50 gamerscore.
You played on a bonus tile
You created your first Multi-Snap
Created a highest scoring snap
Play Tap-Snap in more than one language
Play all seven tiles in a Multi-Snap
Make a snap in each of the following shapes
Complete 100 full games
Achieve 2,500,000 total points
Swap 2 tiles and make a new snap
Achieved "Sore Fingers" and "Addict" and placed in the top 250 of the “Top Player” leaderboards