Here is the full list of all 44 Iggy's Egg Adventure achievements.
Retry a level from the Gave Over screen
Get eaten by a Whale
Die 10 times
Collect 1000 small eggs
Unlock Terry
Defeat the Bull Pachycephalosaurus
Kill 10 cavemen
Die 1 time
Collect 10 large eggs
Collect 5 large eggs
Kill 1 caveman
Collect 100 small eggs
Collect 1 large egg
Collect 25 large eggs
Collect 50 large eggs
Collect 99 large eggs
Collect all large eggs
Kill 100 cavemen
Kill 1000 cavemen
Collect 5000 small eggs
Collect 10000 small eggs
Collect 25000 small eggs
Get eaten by a T-Rex
Escape the T-Rex
Die 100 times
Get Bronze or better on any Time Attack
Get Silver or better on any Time Attack
Get Gold on any Time Attack
Get Bronze or better on every Time Attack
Get Silver or better on every Time Attack
Get Gold on every Time Attack
Defeat the Cave Harvestman
Defeat the Giant Scorpion
Defeat the T-Rex
Defeat the Spinosaurus
Defeat the Caveman Shaman
Unlock Patrick
Unlock Phredrick
Unlock Perry
Unlock all playable characters
Unlock the Dapper Iggy costume
Unlock all costumes for all characters
Watch the credits for Iggy's Egg Adventure
Complete Iggy's Egg Adventure with 0 deaths on a single profile