Here is the full list of all 10 BellyBots achievements.
10 Headshots in a Row
Kill 25 enemies without being hit
Kill 100 enemies without being hit
Kill 250 enemies without being hit
Finish the game without being hit
Kill your first Volt-O-Peter
Kill your first AeroBot
Kill your first TripBot
Survive your first BellyBot
Kill a Volt-O-Peter with a headshot