The Heart of Gold (THoG) is highly inspired by the first two books in the “Hitchhiker's Guide to the Galaxy” series but twists the story, so that the planet Eamon was in the way of a new 'hyperspace bypass' and would promptly be destroyed. Your friend Ford Prefect helps you escape by hitching a ride with The Heart of Gold spaceship, where you will meet all the familiar characters from the first novel. From here, you will go through four well-known but modified scenes from the series before you reach the end.
Some of the puzzles will be easier if you have read the books and played the Infocom game “Hitchhiker's Guide to the Galaxy” but there are still some good original puzzles in it. The puzzles are certainly easier than the Infocom game but the forgiveness rating of THoG is more cruel: If you feel stuck in some of the last three scenes, it is most likely because you didn't find everything there was to find in the first scene. However, the game is quite short once you know what to do, so it isn't that time consuming to start over. There is a built in hint-system. I only needed a couple of hints (which I regretted) but if you haven't played the Infocom game or read the books you might need more. Overall, I regard the puzzles as fair.
The author (Frank Kunze later known as Frank Black) chose to write the game with the Eamon system, which is normally used for combat-heavy IF games, where you can bring character stats, weapons and armor from other Eamon games. However, ThoG doesn't contain combat at all and it is a standalone-game, which means that you cannot bring any stats, weapons or armor into the game.
Furthermore, the game understands seven new verbs compared to a standard Eamon game, whereas commands which doesn't make sense in this game, such as the four standard spells, have been removed. It can be argued that the game is an IF with a restricted verb set, and if you type a word the game doesn't understand, all verbs understood by the game are listed. If you never played an Eamon adventure before, you might want to check out the first option in the HINTS menu (General Help), which doesn't reveal anything about the puzzles in the game. Instead it tells you about how the Eamon parser behaves, which is a little different than modern IF games. Most importantly, you can INVENTORY characters to see what they are carrying and if you want objects inside other objects you must REMOVE them. The parser is primarily a two-word parser, e.g. TALK ARTHUR, though it does also understand phrases like GIVE KNIFE TO ARTHUR etc. However, the Eamon parser has the advantage that you don't need to write whole words, e.g. you may type EX WA instead of EXAMINE WALKIE-TALKIE.
The humor is more or less stolen from the books, which I regard as a good thing since I regard THoG as a tribute game with some original puzzles, and since many authors have attempted to be as funny as Douglas Adams without success.
So if you enjoyed The Hitchhiker's Guide to the Galaxy in any form, and you don't mind the alternative Eamon parser, you will probably enjoy this small puzzlefest.
Finally, some practical info for Linux, Mac and Windows users:(Spoiler - click to show)Unless you want to run an APPLE II emulator to play, you must download and run PC Eamon Museum for your machine. When it starts up, select "Visit Eamon Deluxe 4.5 (2007)". Then choose 1.Enter the Main Hall. When you are asked if you go over to the desk, hit "D". Then choose any of the predefined characters. It doesn't matter which one, since character stats, weapons and armor are not used in the adventure. After selecting a character, you will see a graphical view of the Main Hall. Your character is placed in the top-middle. All you have to do is go one step up using the arrow keys. You will then be asked whether you want to go on a (A)dventure or (L)eave the universe. Type 'A'. Now you get to choose which adventure set to play. Frank Kunze changed his name to Frank Black, so select "The Frank Black Adventures". Answer the questions, select "Play an adventure" and pick "The Heart of Gold". The game is now running.