I've been playing a lot of this. It's a really cool combination of the card-based battle system from Slay the Spire and the multiple board concept in Artifact. For such a niche (for now..) genre, the production values are through the roof. Great visuals, audio and a fuckton of content, none of that early access bare-bones shit.
The skill with most card games is learning how to minimise the risk of getting fucked by RNG, in that area I feel this maybe isn't quite as good as Slay the Spire from a pure gameplay perspective.
In StS you can certainly have RNG fuck up your plans, but often it'll result in you almost losing a round then forcing you to pivot your strategy. I've had some great clutch wins after a string of bad-luck and that emotional rollercoaster is what makes it so fun
But in Monster Train, you can be on an incredible one-in-a-million lucky run and have an almost unstoppable build; then a single hero with a random attribute can just come along and be like "noooope" and it doesn't give you the tools to overcome/avoid it, so 30 minutes down the drain.
On the harder difficulties, you absolutely have to double-down on a very specific strategy too to make progress so the game does get more frustrating the more you crank up the difficulty.