in the TAP and Ti emulation there is "firm drop" it's a non locking hard drop, via up. you do an up down to drop and lock. In TGM there is only soft drop.
There's a simple manual that shows you how to customize basic things, like controls and video settings and the like. Other than some extra simple things (like changing your name, etc) there is no "customization" in Texmaster.
I think "other simple things" covers sound, too. I mean (and I think the OP means as well) gameplay customization, like in lockjaw or Heboris.