Classic Tetris VS. Modern Tetris - Similarities and Differences

So what's the difference between Classic Tetris and Modern Tetris? At first glance, they both look pretty much the same.

With the recent milestone of Blue Scuti, and now Fractal and PixelAndy beating Classic Tetris, I figured it would be a good idea to talk about the similarities and differences been Classic Tetris (including NES and Gameboy Tetris) and Modern Tetris (including Tetris 99, Tetris Effect, Tetr.io, etc.).
----------------------------
Clips used in this video:

   • The First Time Somebody Has Ever "Beat" Te...  
   • Diao vs Blaarg - Grand Finals - Sakura Ble...  
   • Kazu vs Akashirobo - SEMIFINALS - Square O...  
   • NES Tetris Drought WR [Former]  
   • Tetris Commercial for Nintendo  
   • Tetris Tournament Reveals Secret World Rec...  

Music:
   • CHIPTUNE 1.5 Hour MIX (Retro 8-bit music) ...  

Thanks for your contributions!
-----------------
Chapters:

0:00 Introduction
1:11 Similarities between Classic and Modern Tetris
4:24 Difference #1 - 7 Bag System
5:05 Difference #2 - Super Rotation System (SRS)
6:29 Difference #3 - Bonus Scoring
6:52 Difference #4 - Mechanical Differences
7:30 Variations within Classic Tetris
8:40 Variations within Modern Tetris
9:48 Outro