I beta tested this game.
Marbles, D, and the Sinister Spotlight" is a delightful game from Drew Cook (author of Repeat the Ending) that is inspired by the old Zork CYOA books (which I haven't read, but I definitely got old-school CYOA book vibes from the writing here.)
This is a highly polished Parser game with several illustrations, cinematic 'cut scenes' and act changes, several layers of help menus and a lot of independent actions by actors and scenery changes. It has a lot of custom responses as well.
The idea is that you are a highly intelligent cat and you're exploring an abandoned movie theatre with your human friend that you've been locked inside of as part of an adventure. The movie theatre is mysterious and dark, and it's up to you to guide your human around.
The text is rich and expansive, while the geography is small and limited. I'd say that this game is designed (intentionally?) to be accessible to those familiar with gaming in general but unfamiliar with parser conventions and tropes. It has extensive tutorial comments early on, a constrained list of verbs that can be accessed at any time, a list at the top of available locations and important items, and hints in the text at which actions are appropriate to progress.
It's not too long; it's divided up into six acts and a finale, with each act solvable in just a few actions. The story does feel complete, though, which is another reason I think this makes a good game for those new to parser games. I've found that when starting parser games (or playing parser games in a new and unfamiliar language) that it really helps to split up the game into distinct sections, limiting the geography, and keeping a running list of important items makes it so much easier (I write this as I'm struggling with a long French parser game).
The pictures were a real highlight, very evocative and fitting of both the setting and the style of writing. They worked for me in both downloadable and online versions but I preferred the overall look of the online version.
The HELP text at the end suggests that the game was made with learning and/or teaching new Inform techniques like scenes in mind. I hope the source code becomes available, as the game does enough neat stuff that I think people would benefit from seeing examples of it.
I appreciated the little 'paw pictures' that let you know when to press a button, as there are often large amounts of text at once.
Veteran parser players will enjoy the Zork references (which manage to be both pretty faithful while also being creative) and newcomers will appreciate the help systems. Fun and not too long.