Here is the full list of all 18 Grub Gauntlet achievements.
You completed 40 levels!
You Completed 30 Levels!
You completed 20 Levels!
Uploaded a workshop level!
1000 Bombs Exploded
100 Bombs Exploded
You completed 10 levels!
You completed 5 levels!
You completed 50 Levels!
5 Levels Uploaded
10 Levels Uploaded
20 Levels Uploaded
Complete 5 levels without resetting
Complete 10 levels without resetting
Complete 20 levels without restting
25% Win Ratio
50% Win Ratio
75% Win Ratio