This is free on GoG so it's hard to be too critical of the whole thing. The game itself gives you plenty of caveats before you even start playing the game. This is firmly a visual novel, but even by visual novel standards this feels very limited. You're basically stuck in place and can only look around and click on things. There isn't any fail state. There isn't any exploration. You're basically just clicking your way through the iconic short story Dagon.

The visuals, for what they are, are decently done. I did feel that some of the visuals didn't match the prose of Lovecraft. I found the reveal of the titular Dagon to be particularly disappointing, which is a real shame since it's kind of the whole "pay off" of the story. I also thought another mismatch was around the description of a Bas-relief of a giant monster killing a whale. The actual image just shows the monster just kind of vibing next to the whale... not looking like they are attacking each other at all...

It's a very faithful adaptation of the short story. No more. No less.