I quite like this game, as a TL;DR I'll say that the game has good presentation. it makes the most out of RenPy's rudimentary framework. Although the models are a matter of taste I find them appealing, unique and with a good amount of eroticism. Writing is above average for these type of games. And the cherry on top is the Dev's work ethic. My one pet peeve however is with the porn side of things which I'll elaborate further down.
Presentation
Dev puts great effort into making this look and feel like a proper videogame, menus and interfaces generally feel snappy and have distinctive flare, you can tell right away that thought and care was put into them.
Gameplay
Probably one of the more divisive parts about Space Journey X, I think the game systems play off each other well and don't overstay their welcome, as you recruit crew you can delegate tasks to other people and hold more of a management role which I quite like, do keep in mind that I'm quite tolerant for grind and for me this game is almost right on the edge of being annoying but I enjoy it for what it is, I find it gratifying when number go up. My one minor complaint is that I wish it was a bit more integrated with the narrative, mainly how the crew involve themselves with the gameplay and the story, which there is some of that but I wish there was a bit more.
Sound
Serviceable, doesn't stand out in a negative or positive way. The music and sound effects fulfil their purpose and they add to the overall presentation
Visual Art
Models look good, they are unique and I like the lewd costumes the cast wears, especially the default starting ones. Nudity comes rather quickly and abruptly, I would've liked it to be a bit more built up, but that's just my preference.
Writing
Story follows a typical space adventure set up with a comedic tone and it's fairly consistent in that regard, it's very cliched but I think that's a good thing, it's fun to see how the erotic beats tread on familiar territory. In western erotic games sci-fi is not done that often so I appreciate seeing it when it does show up. Writing's biggest strength however is how it reads with no issues (like it was written by a native speaker or someone with very fluent English) which is always nice to see. My one complaint is with characterization (mainly with the female crew), although the girls have different personalities they share common traits, they are all somewhat taciturn and they express themselves in a very similar manner
Porn
I think porn scenes are y.v.'s biggest weakness as a creator and the one thing holding him back from being a top 5 developer (in my eyes). I'll start with the good, I enjoy the light BDSM theme that the game has, I feel indifferent for it most of the time but I can enjoy it sporadically, out of everything I think this is the one thing he really excels at. I enjoy the transactional and emotionless nature of some of the scenes... up to a point. The scene structure usually goes something along the lines of: MC convinces girl to do sexual act -> Sexual act starts -> 3 second animation loop back and forth -> MC cums -> End, this makes it feel like you are watching a guy fuck a blow up doll which is also something that happens within the game, so the contrast is more stark when the girl has the personality of a dead fish throughout the whole thing. There are a few exceptions to this and these are the scenes that I like the most where there is a set up, different scene transitions, dialogue between the characters, different emotions, etc. I'm the type of guy that prefers still images with dialogue and writing to carry the scene and in this case the animations are not that spectacular to carry the scenes alone
y.v. as a creator has huge potential (imo) he has made huge leaps from his past game and even in Space Journey X you can see growth between each update. Whatever direction he decides to take I'm eager to see what he has in store in the future.