Excellent grand strategy game, with an emphasis on grand. The scope of a single game can be absolutely massive.
Just like lots of other great paradox 4x games, the formula is solid -- create your ruler and their faction, go forth into a pretty big world, colonize and throw down with rival factions. But that's just scratching the surface; Stellaris is full of anomaly events, sudden galaxy-affecting stories and unpredictable relations with neighboring aliens. No game plays the exact same, and the customization allows you to fine tune your faction to exactly how you want to play the game.
The atmosphere is solid. A great UI, solid visuals improved drastically by mods and a top-notch soundtrack bring space to life, while well-drawn characters and pretty space battles draw you into the minutia of a gargantuan game. A+.
Worth getting, but it has that same very expensive paradox DLC formula. Grab the base game and maybe wait for a sale for the less essential packs? The expansions and story packs are great but the race packs are simply overpriced. Utopia, Megacorporations and Synethetic Dawn are top notch. 9/10 epic strategy stories.