Here is the full list of all 44 Secret Agent HD achievements.
Complete all achievements.
Destroy 10 mecha-spiders
Spend at least 60 seconds under the water
Finish any level in under 60 seconds
Stack two barrels, one on another
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Finish Episode 4
Collect all island treasure.
Collect every flag in the game
L10 without killing any enemies and with a perfect health.
Finish 5 custom maps from the Workshop
Destroy crawler bot while in the air on medium or hard difficulty.
Kill an enemy while wearing a jetpack
Finish Episode 3
Hold 6 keys in your inventory at once
Get maximum rapid fire
Collect 100 tombstones
Collect over $1000000 worth of bonus items
Finish Episode 2
Finish any episode on HARD with 35 ammo or more
Kill 50 Ninja's
Catch 50 hidden coin bags
Use the teleporter 50 times
Complete any episode without taking damage.
Complete any episode in one session without loading.
Complete any episode on hard mode.
Disable laser grid 20 timesCHIEVEMENT_DESC_23_16
Destroy 10 tombstones
Collect 25 toothbrushes
Blow up enemy with a Dynamite
Finish Episode 1
Collect All Magnifiying Glasses in any episode
Complete any level without killing any enemies
Finish a level with an extra key in your inventory.
Die in water
Get confused and slowed down at the same time.
Life is better in the hot tub.
Finish any level with a perfect score
Collect all SPY letters in the right order
Collect SPY letters in wrong order
Finish any level