He made many attempts but failed. When he lost all of his lives, he somehow lived. And when he died again, he saw a 1 next to his lives. PewDiePie found out they were negative lives. He has over 80+ failures. He still beat the 1st level eventually.
As shown in Part 1 of Cat Mario, he ran into almost every danger on the first level, and it took him many attempts to get through the very last obstacle. When he won, he had a big celebration about it.
While he was attempting to get through the second level, he accidentally triggered the "Poison Block" for the first few tries. After getting the hang of it, he jumped to the pipe only to get killed by a balloon blob, causing him to bash the keyboard out of frustration after dying in the game.