I'm writing this for EA version of the game, so if dealing with unfinished product is not your thing - stay away for now and wait for a full-game release.
Getting this out of the way from the start - let's see what we have so far.
Another Stardew Valley / Harvest Moon clone?
Yes... an no.
Coral Island has enough uniqueness to stand on its own in farming sims genre, but enough similarities so not to feel lost going in blind.
3D is a nice twist for me, other people will feel more in their element with this. Anyway - looks good.
Visuals are awesome, music is very nice (I keep humming along the main theme through the day). Story - enough is there already to keep player interested in getting to know more, and there's a promise of fleshing it out in the future.
Gameplay - very, very familiar in its basic elements, but with some new things thrown in here and there. You get to clear the land, plant, tend, and harvest your crops, raise animals, fish, mine, also - catch bugs and critters, and clear trash. Yes, there's an environmental awareness message tied in, and some people will find the way it's done somewhat (or very) controversial - I don't mind bad guys painted dark as coal in games.
A lot of areas to explore, tons of activities to do - you will find that days in-game are going too fast, even when you put it in "slo-mo".
As for NPCs interactions and dating aspect of it - did I say already about amazing visuals? Same goes for this part. Everybody is absolutely lovely and dateable (and many non-dateable) characters are just plain gorgeous. And selection is just delectable. Who needs Sims when you have THAT?
Now to the negatives...
Bugs, tons of bugs. And glitches. Also typos and other minor and glaring linguistic errors that even I (as a not-native English speaker who makes a lot of mistakes myself) find off-putting at times. I encountered game-breaking bugs once or twice, had to start another save 1 time and just restart the day here and there. Some other people have different experience.
A lot of features are not fleshed out, some are just hinted at. So many areas are not done yet, some are there to walk in - but just empty. Often you have no idea (without asking community) if something is not there yet, or not working properly, or something else entirely. Some aspects of the game (like fishing and catching bugs) are just frustratingly difficult at times in current state for people who don't have lightning reflexes or have older computers (or both). Missing textures, memory leaks, loading issues, stuttering here and there... But a lot of it is expected when you dealing with Early Access, and from what I see - developers are working on the game diligently, so hopefully all that will be dealt with in time.
So - bottom line.
Would I recommend this game - yes, even in its current state.
I've got over a 100 hours of play time out of it already, and there's a promise of more fun to come. And the price is not too big for what we have now, with (again, hopefully) a bigger and better product in the future.
This game has a lot of potential, and I would like to see how it will turns out at full release.
But remember - Early Access is not a full game, and not polished game.
If you are ready to deal with current (and possible surfacing) issues - go ahead. If not - wait.
If you get in - you also can have a say in how Coral Island will look and work in the future. Developers do listen to the community, so it's a chance for you to participate and make your voice heard.
I will definitely play more with new updates (not saying that I'm putting it off a the moment!), and very eager to see Coral Island's full release.

P.S. I did get the game as a gift from one of my friends - so here's a BIG THANKS to this awesome person - you know who you are! <3

Well, I am finally done with the game - at least the current version of it, so I guess it's time to update my review...

I'm keeping initial one here, and adding my final thoughts after that.
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I'ts not a full review - just a first impression. But a very favorable impression!
So far I've played only just a bit over 3 hours, but not because I don't like the game - quite the opposite! But real life demands, and there are only so much time in a day...
I went into this game blind, without reading reviews or guides or wiki (is there a wiki?), or watching videos. But since I've played Stardew - it was easy to figure out what's what. But the game does a good job of guiding you even if you don't know what you doing at all at the start.
Art, music, vibes - I fell in love with the game in the first five minutes, and after almost 4 hours - it doesn't disappoint.
Sure, I would like some QoL changes in the future (why the heck planters don't stack? and why fighting monsters cost energy?), but overall - it's pretty and cozy and charming...
I'm definitely coming back for more!
Now, how can I rearrange my schedule to get more play-time?..
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So... I did find time, and I did finish the game.
Conclusion - will I recommend this game after all? Yes.
My stance is still stays pretty much the same.
Yes, there is room for improvements - and I saw some QoL changes made even while I was playing. Developers do listen and actively engage in the community, so I have high hopes for the future too.

Characters are lovely, if maybe a little bit simple (but that's not a big drawback in my eyes).
Graphics, art - 10/10, vibrant, easy on the eye, absolutely lovely.
Music - 8/10, nice, simple but not simplistic, though it gets repetitive after a time.

Gameplay... that's what a lot of people have issues with.
Many say it's grindy and repetitive, and I agree - to a point.
It's a farming sim, and so it is cycling through the same motions again and again, with some variations. But that's to be expected in this genre. And if you are in need of some high-paced action - why are you looking at farming sims in the first place?
It's not easy to speed-run LKG (at least currently), but to me it looks like it's by design - it's a feature, game is meant to be played at a leisure speed, not rushed through. And if you are feeling bottle-necked at some point - you are probably trying to force your way forward disregarding other areas.
A lot of mechanics become easier and more manageable as you progress and upgrade your equipment (and one mini-game can be just turned off entirely), and money isn't as hard to get as it seems at the start.
That said - yes, game can and should be improved, but as I said already - developers are on it...

My biggest disappointment as of now - there are no blue antennae! And no way to change the color of those green one that are in the game. So - no way to cosplay as an Andorian...

P.S. To my friend who gifted me this gem - thank you, you are awesome! <3