Playing this game makes me happy. It's not particularly thrilling or difficult, but something about its central premise - you control four cute elemental giants and you use their powers to be generous to the tiny humans that scurry around on the surface of your planet - just fills me with an understated joy. I mean, in order to get an achievement, I ordered my stone giant to destroy three human villages with an earthquake, but that brief spat of violence aside, I love that I'm playing a game where you win through the expression of kindness.
The big weakness of Reus that I'm noticing so far is that it is literally a one-dimensional strategy game. As in, your location on the map can be defined by a single natural-number coordinate (although, to be fair, in a super-technical way, so can any strategy map that takes place on a grid). You can move your giants left and you can move them right, and you can place a single improvement on each tile (though these improvements can be upgraded in various ways). The goal is to maximize your villages' prosperity through stacking adjacency bonuses. Since there are a lot of different potential upgrades and interaction bonuses, there is the potential for this to become a very complex strategy game, but I expect that in the long run, I'll eventually discover an optimal path.
Each game of Reus is either 30 or 60 minutes long (though you can eventually unlock a 120 minute mode) and in that time your goal is to hit one or more of the game's benchmarks, like getting a village to 200 prosperity using only animals and minerals. If you succeed, you unlock more upgrades for your various fertilities and special projects for your villages. Presumably, these new things then allow you to chase after even more difficult challenges.
Honestly, I don't expect to be challenged by this game. I think it will mostly be an exercise in number-shuffling that just happens to be visually represented with a charming cartoony pastoral aesthetic. But that's not a problem for me. It will be relaxing to sit back and optimize numbers without any great pressure to conquer or dominate. I've yet to dislike any game that lets me plant strawberries.