You are standing in a cave... is a parser-driven adventure of perennial adventuring. Stuck in the title cave with only a random collection of stuff in your pockets, you, the viewpoint adventurer, must unstick yourself and escape. The environment is full of props and clues designed to speak tantalisingly to each other in the language of puzzles via your adventuring brain. The climbable, the ignitable, the combinable; they're all here.
This is plainly not a game for people who dislike puzzles. There will still be a dropout rate amongst people who do like puzzles based on either roughness of implementation or lack of upfront glamour / hookiness. Also, there's the issue that the game's title could as easily be read as a joke about the banality of some old adventure game as the unremarkable but straight-shooting meat and potato entity that it is. Though it is a more versatile statement than it first appears to be. Consider this existential juggernaut of a title: You are standing in a cave / You are dying in a sewer.
While cave's first room looks dull and prototypically cavey, things quickly become more involving if you give it a room or two.
The game's tone is encouraging with a dash of wide-eyed. The adventurer seeks answers to age-old questions like, 'How do I defeat this giant venus flytrap?' or 'What really happened when I turned that dial?' and is excited about the progress s/he makes. The game's positive tone acts as a helpful counterweight to its many rough typological edges and programming oversights. Tedious users of Inform 7 like myself will repeatedly nod their heads during this game while muttering things like, 'Oh, I know what the author forgot to do THERE.' Probably its weakest areas are in verb coverage and the offering of alternative phrasings for apparent actions. This is partly mitigated by Cave's going in for lots of USE phrasings. USE A WITH B (à la Quest) has been implemented all over the place.
The game's generic USE leanings fit in with another observation I made: That Cave often feels like a graphical point-and-click adventure rendered as prose. I don't mean that in a redundant way, given that point-and-click adventures owe their existence to prose IF. I mean that it takes aesthetics that were added to adventures when they were transitioning into graphical form back in the day and brings them back into the all prose realm. I refer to aesthetics like the extended depictions of transformations that occur in the environment when puzzles are solved. Objects revolve, rise, shine, glimmer or rotate at relative descriptive length, all to the pleasure of the adventurer protagonist. It's visual, and the physical movements are important.
My playability assessment for Cave comes down to: How completable is it in spite of its tech troubles and the lack of hints or walkthrough? I am the kind of person who's reticent about walkthroughs and I was able to clear the game. The external help that helped me was Anssi Räisänen's review of Cave (he'd already completed it) which says that solving certain puzzles isn't essential to win. This freed me up to move forward, since I was sure I knew what I had to do with certain objects but I couldn't get my ideas through the game's creaky parser – or, I didn't trust the parser to give me feedback that I was wasting time in those cases where I was. So, although Cave lists no testers and has lots of apparent bugs, you can clear it. I had fun doing so.