I see how he did it now!
1. He went into all Parallel Dimensions, except the ones at Lv. 15, Lv. 23, Lv. 33 (he didnt have the key), and whatever other ones he skipped in the portions that he skipped it the video, even if it meant losing a few lives
2. Whenever an item that would've ended the level was offered to him, he avoided it
3. He always went after the Large Crystal Order in each level, and was succesful a good portion of the time
4. He got a Moneybag on Lv. 15 and managed to keep it until Lv. 46.1
5. He got a Golden Igor at Lv. 17.
6. He went through the Lv. 16 PD and the Lv. 25 PD WITH the Moneybag active
7. He skipped a lot of it in his video, but it looks like he went quite a ways into Hell
8. He got a Candy Cane at Lv. 62
9. He used the Meluzin Key at Lv. 78
10. The videos stop at Lv. 97, but based on his score, I'm pretty sure that he beat Tuber
