Some of the trope marks overlap some of the vowels. We know. We're working on fixing this.
In keeping with modern typographic conventions, when a cholam chaser appears next to another dot (for example, to mark a shin,) both dots are printed. This is often very helpful.
In keeping with Masoretic documents, the dot indicating that a vav is a cholam is printed next to the vav, not directly over it. This probably isn't what you want. We're working on it.
You can only get about 1-page of Tikkun text at a time.
Our text comes mostly from the Leningrad Codex and BHS. If you think you've found a typographic error, please let us know.
You can create a Tikkun from any book of the Bible, though it's hard to image what you would do with anything but the Torah.