Ad Verbum is solely a puzzle game (no story or plot). Unlike traditional IF puzzles, the puzzles in Ad Verbum are word puzzles, mostly of 'guess the verb' form. In general, I detest 'guess the verb' puzzles, but this game succeeds beautifully by creating logical constraints for the verbs. While playing it, I found myself happily mulling over synonyms for 'take' and 'exit'. The writing in the game is very clever, and the author does an exceptional job of following the rules presented in the game, managing to give entire room and object descriptions using only, for example, words that begin with 'w'.
The game is relatively short. Most of the time you spend playing it will be spent thinking over puzzles. Ad Verbum is great for delivering the 'ah hah!' moment of a cleverly solved puzzle. It's also a terrific game for involving others in the puzzles. Normal IF puzzles are difficult to share with others, but it was simple to turn to my husband and say "I need a word that means 'exit' that begins with 's'." Indeed, my husband provided the necessary solutions for at least two of the puzzles.
This game is highly recommended as a diversion from more traditional IF, and is a must-play for any puzzle-lover.