Angry Green Thing is an achievement in Run 3.
(Note: Since you can only earn this achievement with the Lizard, it will be the only suggested character.)
To complete this achievement you need to destroy all the crumbling tiles in Level 63 as the Lizard. All of them. The problem is that all the crumbling tile that you will need to determine which crumbling tiles are isolated and which ones are diagonal from each other (stepping on one platform will have a chain reaction and will crumble the diagonally adjacent tile).
When you start the level, jump to the crumbling tile platform right in front of you, then immediately jump to the left to hit that crumbling tile platform, or you will not have another chance. Then you will see two rings of crumbling tiles and jump on both of them.
After landing on a regular tile ring, this is where you really have to pay attention to the placement of the crumbling tiles. Here there are a bunch of semi-rings that do not all have to be jumped on. The first two semi-rings are diagonal from each other, and therefore you only have to land on one of them. The next one is completely isolated, so you must jump on it. The final two are once again diagonally next to each other, and you will have to just jump onto one of them. Then jump to the next normal tile.
Finally, this is where this achievement gets easy. There will be three more rings of crumbling tiles that you will need to jump on and then a final normal tile ring. Last but not least, there is one more arrow-shaped crumbling tile platform pointing to the end of the level. Try to jump to near the end of the platform so you will not miss the final jump to success.
It may help if you fail a couple of times as it will eventually make the Lizard slower and cannot jump as high. However, this achievement can also easily be completed with the Lizard at its normal speed and jump height.