Here is the full list of all 29 Rocketbirds: Hardboiled Chicken achievements. It takes around 10-12 hours to unlock all of the achievements on Windows.
Kill 20 enemies while brainbugging
Brainbug 30 enemies
Brainbug at least one penguin from each of the 7 penguin ranks, including Putzki
Kill all penguins stationed on the zeppelin in Chapter 3 (Single Player)
Kill Brno with the knife
Overthrow Putzki and liberate Albatropolis
Find all 45 Signs
Kill 6 helicopter penguins with their own missiles
Kill 3 enemies with one grenade
Stack all 3 crates near the end of Chapter 11 (Single Player)
Punch or kick 100 times
Kill 30 Penguins as they step out of a door
Escape the large zeppelin with 40 seconds or more on the timer
Kill all penguins stationed on the big zeppelin in Chapter 8 (Single Player)
Kill all penguins stationed on the small zeppelin in Chapter 8 (Single Player)
Kill 10 enemies, each with one gunshot
Kill 6 enemies with the bazooka
Kill a helicopter penguin with his own missile
Find 20 Signs
Kill 2 enemies with one grenade
Brainbug the penguin above the star in Chapter 6 (Single Player)
Juggle an enemy for 10 seconds
Find 3 Signs
Launch the silo missile
Carry the other cooperative player for 500 meters in the same chapter without dying
Complete the Cooperative game mode
Kill 300 penguins or clones
Kill 100 penguins or clones
Kill an enemy by knocking him into a laser door