Until last week, I had no idea that Infocom games were still available on current platforms. After downloading an iPad app, I had the pleasure of trying my first commercial game after 5 years of free interactive fiction.
The manual and feelies were great, and the parser was very smooth, with great runtime. I missed several of Inform's features, especially when killing enemies. Overall, the game felt thoroughly tested, and a large number of the annoying features of MIT Zork were removed. Examples include a better coal maze, some of the smug writing, and better correlation between exits and etrances of nearby rooms.
I thought at first it was silly to split up the game into three, but having started Zork II, I am really enjoying the expanded versions. Very few of the free games I have played rival this kind of polished game, with Curses! and Anchorhead as my main examples of great gameplay.