There's a certain type of player that will find this game immensely enjoyable. I thought I was that type of player, but I wasn't. I don't know how exactly I'd peg that type of player, either. I suppose the type who would try to 100% a Metroidlike. More specifically the type who takes exhaustive notes on every item in a game that they need to go back to later maybe. Well, let's try to figure it out together.
I thought I enjoyed exploring game worlds. After playing this game I'm just not sure anymore. It takes some effort to pinpoint why I don't get so much out of this game. An easy way out might be to try to blame the abstraction involved. But that isn't really it. I've gotten a lot of joy out of slowly mapping out and understanding an RPG overworld. I think NES visuals generally convey some of the best auras of mystery entirely due to being vague. So abstraction itself isn't at fault here.
One problem might be that it takes a very long time to feel like you really "conquer" anything in Ramble Planet. No matter where you go or what you do there's pretty much always something you can't access yet. Metroid games balance this out by giving the player two forms of progress: the linear main goals of the story that just require you to traverse areas, and the more optional things to collect. You never feel too bad about all the stuff you leave behind because you're still accomplishing something by just traversing the areas. In Ramble Planet collecting stuff is the only goal so everything you leave behind turns into a mountain of regrets for later. The things you need collect are also so very similar that they don't form much in the way of memories or desire in the player (a level X monster doesn't really create a memory regardless of its text description).
Or maybe the real problem is that nothing feels quite connected together. There's not much sense of "history" to these places (ironic given there are signs all over the world telling you about their history). There aren't any transitions between moods. There's no set up to areas (you remember that one water pipe you cross through in Super Metroid long before needing to enter the water area? things like that). The game seems to occasionally change music tracks based on area, but only loosely. It's probably just that the game is so dense with different areas that none of them really get to breathe individually. I haven't played a ton of the author's other games, but I recall Dreg Sector being able to establish mood with areas and events very quickly by just using a few text boxes. Ramble Planet leans heavier on its visuals, and they don't seem to quite pull it off due to their density (Of course being a gigantic mishmash things thrown together on one planet is the entire point of this flavor of scifi to begin with, but it doesn't seem to work out as a world to be explored).
I played the game for about an hour and picked up 17 ship parts. That's not very far, I could see the game getting more interesting later on. To its credit, after a few laps I was getting a pretty good idea of how the world connected without having to think about it thanks to the raw density of landmarks (though I was clueless at remembering any points of interest for later on). What broke my interest for good was the game's introduction of mechanics that are insulting to the player's time: multiple paralysis clouds that make you wait around for text boxes, a casino that boiled down to holding down a directional button until you won, and invisible mazes. They're noble attempts to diversify the feel of exploration, but they just came off as slogs to me personally (there's a good chance that items you get later in the game might allow you to bypass them in more convenient ways as well, and you could certainly raise an argument that they're attempts to bring certain RPG nuisances into a simpler format). At any rate, I recommend giving Ramble Planet a try if this type of exploration game is your thing. You'll either love it or hate it, but you'll probably learn something in the process.