I agree with @HanonO that, while beginners should have no problem getting into Counterfeit Monkey, it’s better played later in one’s career in order to appreciate what a triumph it is.
I disagree with anyone who claims that a beginner game needs to be easy. Anyone taking that position needs to provide an explanation for how ADVENT and Zork managed to become wildly popular even though, when they were first released, everyone was a beginner because there was nothing else to learn from.
A good beginner game, first and foremost, has to be a good game in general. This is where I dock points from ADVENT and other early classics, because they’re full of things that are now understood as simply bad ideas, like the limited light source and (most unforgivably) the capricious RNG deaths. The difference between a good beginner game and a good expert game is that a beginner game provides a good ramp-up that introduces the conventions and tropes of the genre, while an expert game assumes you’re already familiar with them and tries to spare you the cliches. A beginner who tries to play a game not intended for them may stumble on things that were never meant to be puzzles because the author assumed they’d be an autonomic reflex, like remembering to start off with “X ME” and “I” and examining everything in inventory, or searching under every bed and inside every drawer and cupboard. Trivial “puzzles” such as those are a good way for beginners to start off, especially while they’re getting a handle on the parser. However, a game that presents “*** You have won ***” without ever moving past such finger exercises is short-changing the player. It’s like an action game that ends as soon as it’s taught you the controls, or a workout program that sends you home after teaching you lifting technique and refuses to put any weight on the bar. Games need gameplay!
There’s some great puzzleless interactive fiction out there. Shade is one of my top ten favorite games. But it’s an acquired taste. I was chagrined that it has several votes on the (original) IFDB poll, because in 2000 I tried introducing to a beginner (specifically, my mom) and the result was a disaster. “Okay, okay, everything’s turning to sand. So what? What am I trying to achieve here?”. Conversely, she had a lot of fun struggling with Hitchhiker’s Guide to the Galaxy, even though she never got far and on its merits that game seems like a sadistic thing to inflict on a beginner.