Version 1.2 of Tetris - The Dark Descent. Provides a full conversion option to remove the jitter, as well as a new levelling system and high scores in the save-file name. Installation instructions for full conversion and/or custom story mode provided in the readme file.
Whilst a few people and myself have given this mod a good test, bugs may still exist, and I highly encourage you to post any you find so they can be fixed in later versions.
New Features / Changes
Options for this new version can be changed by opening up the file called "tetris.hps" and changing the two variables at the top - information on this is specified in the read-me.
The level system was overhauled to provide a more noticable speed-up between levels, and balance out the incredibly fast levelling to level 10 early on. The game starts to get difficult at about level 5 or 6 now, and you can change the difficulty settings in the script file with an option now too.