Sunny Side Up - 20G (Original Achievement)
To get this Achievement, you must defeat the Death Egg Robot.
To get to the Death Egg Robot you must first clear Area 1 (Green Hill, Chemical Plant, Sky Sanctuary). This will cause the Challenge Gates for Area 1 to appear. Above each level there is a key covered by a shadowy aura. You need all 3 keys to access Death Egg Robot. To remove the auras and get the keys you must complete 1 Challenge Gate in each level. Once you get all 3 keys, run over to the far right and the keys will appear and unlock the door to Death Egg Robot.
In battle, you'll start out by waiting for DER to target you, once it locks on, move out of the way and it'll punch its fist into the floor and retract it. Shortly afterwards it will jump and try to land on you. You want to move behind it and hit it in its green and black rear end. After repeating this a few times, you'll appear at the top of the elevator and DER will launch you up to the new area.
Here you will see a few blue platforms, stepping on them will make bombs appear with timers. Your goal is to ready a bomb and wait next to it (dont touch it!) once DER locks onto you, move out of the way and it will punch the bomb and get stunned momentarily. This is your chance to jump onto its hand and roll up it. Once you reach it's shoulder, press the A Button to jump up and hit its head. Repeat this again to finish it off and get this Achievement.
Below are videos of mine showing how to complete the Challenge Gates and defeat Death Egg Robot.