Two-sentence review - a decent pass-the-time game, RE is a mix of FTL and Sunless Sea, without living up to either the fun combat mechanisms (FTL) or unique atmosphere/writing (Sunless Sea) of them. Graphics are fitting and nice, but the game itself gets repetitive rather soon.
To elaborate, the game itself is really fun... but only for a while. I've seen people on Steam with like a hundred and more hours on record and I can't imagine how's that possible, but I guess there are some players who prefer this, kinda sheltered, gameplay.
The combat, while challenging, isn't exactly complicated or diverse. It boasts three different approaches - aggressive, devious and friendly - which can easily be translated into standard RPG language - physical attacks, abilities and magic - but with fancier names. I've read that you should carefully choose the style of combat, so you can exploit the weaknesses of your opponents, but you can easily win most fights by just doing what your characters do best - basically using their strongest attack (+ sometimes healing your party, since most enemies can really hurt you if you let them/get surrounded).
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Boss fights are, like, two-three difficulty levels above regular fights, which might seem unfair sometimes, since you've only got a three member party and your opponents often outnumber you by quite a few heads. But that is almost negated by the fact, that you only have to kill the boss/unique enemy to win this kind of fight - you don't even need to scratch the other bad guys.
The real magic, for me, lies in the game's writing. It's fun, easy, lighthearted. As I've mentioned in the beginning, don't expect the kind of writing (atmosphere) as shown in a polished game like Sunless Sea. But that's fine - it's supposed to have this easygoing, relaxed tempo. The non-violent events are kinda fun, but basically come down to stat-checks and wheel-of-chance rolls. Still entertaining though, mainly because of the different abilities you can choose for your party members, and their impact on the expeditions.
Expeditions themselves are one like the other, but just with different backstory/setting. It all comes to - explore the map, gather as much resources as you can without getting killed/starving yourself, get to the big boss fight and just hit 'em over the head.
I've played only for like 5 hours, so I might have missed something, but I think I've covered the core. Not really worth the 20€ if you ask me, but still a fine game.