The Wizard's Pen is a word guessing game, where the player must write the name of objects by analysing portions of their pictures. Each stage is a collection of 16 pictures and objects sharing the same theme.
The main interface shows a blank page from a magic book, where clicking anywhere on it uncovers a small square of a complete object picture. The player must guess the object and type its name in a tab at the bottom of the screen. The game accepts the most common synonyms and variants for the names, and has tolerance for small typing errors.
A candle at the left side diminishes with every opened square, allowing 8 clicks per page. A number of stars are received for each correct answer, with less clicks awarding more stars. When the candle is a small stub, clicking on the wick smoke reveals the object, but the player doesn't receive any stars.
In some pages the image is not hidden, but distorted beyond recognition. Instead of uncovering it bit by bit, each click on the messed picture clears it slowly, and at any time the player can guess the object by typing its name.
An incomplete picture appears between stages, with missing bits listed at the right side of the screen. The player must click on the places indicated by the list, where the magical pen will draw the missing parts.
At the start of each stage, three magical potions can be taken from a selection of nine. They sit on a shelf at the right side of the page, and can be used at any moment. The perception potion increases the size of the uncovered square. The freeze potion stops the candle from decreasing in size for a few turns. The anagram potion shows a word made with the same letters of the object name. The drippy ink makes the square reveal a bit more of the picture, by making it drip down the page. The hint potion shows a clue about the object. The crystal ball shows three successive objects melded together. The clean slate resets the candle state, erasing all the revealed parts of the picture. The swirl potion paints a spiral on the page, revealing parts of the picture. The silhouette shows the object contour for a few seconds. The lightning shows the complete picture for a brief moment.
The stars collected in every stage are used to open sketchbooks with extra levels, that can be accessed at the main menu.