You can't buy the game for your device (because it's not available for Android) instead you need to buy the game for Windows operating system and then you need to use GemRB to emulate the game on your Galaxy Tab. GemRB is open source and it's available in the Google Play store or our Android Informer section.
Here are the steps required in order to play the game on your device:
- Install GemRB from one of the links provided.
- Buy and install the game on your PC (full installation is required)
- Copy all folders and files (except the .exe ones) from Planescape Torment installation folder on your PC to app-data/net.sourceforge.gemrb folder on your device SD card.
- Edit GemRB.cfg in the device's text editor and follow the instructions you find inside the file.
- Start GemRB, configure controls and then run the game.