Instructions:
1) Download the "RTT2patch v1.0.xdelta" patch file
2) Download the xdeltaUI patcher program from: https://www.romhacking.net/utilities/598/
4) Put downloaded files from step 1) and 2) along with the original RTT2 ISO in the same folder
3) Double-click on the the Xdelta Ui.exe
4) Select the "RTT2patch v1.0.xdelta" patch file under the "Patch" box
5) Select the original R-Type Tactics II ISO that is in your possession under the "Source File" box
6) Fill in how you want to name your patched ISO, e.g. "RTT2patched.iso"
7) Click on "Patch". Depending on your PC it may take seconds to minutes. The program will let you know when it's done.

For more information, go to:
http://www.romhacking.net/forum/index.php?topic=20725