That was indeed the original premise of NotEye. However, NotEye can also communicate directly with the game, which is easier to program, more convenient (system console roguelikes in Windows require an extra window for the original game, and libtcod requires using the correct version and inter-process communication), and much more powerful. This is done in Hydra Slayer, ADOM and PRIME. For example, both in ADOM and Hydra Slayer, smooth sprite movement (mentioned by Quendus) is done by NotEye asking the game about the unique ID of the monster at the given location, checking the memorized location of the monster by this ID, and animating the movement. In most cases, it would be possible for NotEye to analyze the console for this data, but this would require probably quite a difficult algorithm and still would fail in some cases (like, a threat room in ADOM filled with rats, which looks great with smooth movement).