If just by looking at the screenshot published on this page you get the impression that you have already seen this game, you are not wrong. The Witch is in fact a remake of the classic Cauldron from Palace, made with Arcade Game Designer. Compared to the original, sprites are somewhat slower, the map is slightly smaller and has a more linear structure, and most of the screens in the platform-based part have been simplified. On the 128K, some background tunes - at times too lively for the game's "dark" setting - play along while the player-controlled witch wanders around.
Apart from that, the goal is always the same: you must find the ingredients of a magic potion that will allow the protagonist to become the queen of witches. The small simplifications make The Witch a tad less arduous than Cauldron, which was already quite challenging.
If you loved the old Palace classic, you will also love this new version; if you didn't... well, try it anyway, you might change your mind.