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