Here is the full list of all 24 TwinCop achievements worth 1,000 gamerscore.
Complete the training.
Complete chapter one.
Complete chapter two.
Complete chapter three.
Defeat Mecha Pontoon
Cut the correct bomb wire 3 times with less than 5 seconds remaining on the timer.
Drive TwinCar to its destination without hitting any other cars.
Kill 10 enemies in the grocery store with fruits and vegetables.
Leave the grocery store armed with fruits or veggies.
Fill the TwinCar with gas without spilling any.
Drive TwinCar to its destination while only driving in reverse.
Destroy all of the PopTop vending machines.
There's always a secret behind the waterfall.
Find all of the friendship bracelets.
Attract 250 enemies with May's Donut Trap ability.
Send 75 enemies away with Brody's Holy Mackerel ability.
Tase 250 enemies with Will's Super Taser ability.
Snipe 150 enemies with Angela's Laser Snipe ability.
Set 250 enemies ablaze with Josie's Flare Gun ability.
Block 500 projectiles with John's Baton Block ability.
Grapple 75 enemies with Killa Kill's Hookshot ability.
Punch 250 enemies with Dr. Fist's Spectral Fist ability.
Use Twinsanity 100 times!