Credit due to the masterful wizard, Kirjava, for their excellent work on this new take on the cult classic. TetrisGYM. This is the latest V3 release.
It is a modification of NES Tetris and includes a wide variety of alternate gameplay features which can be toggled at your leisure.
Please check out this link for more info on these features:
https://github.com/kirjavascript/TetrisGYM#readme
All features are present except for the save-state/load-state feature which isn't functional at the moment.