The style of the game is reminiscent of Tove Jansson's comics but I am not quite sure if it's directly lifted from them. Whichever, it's very nostalgic and cute. Playing is very easy and quite fun. The game is available in Play Store on android for free though there are some adds in the game and you can buy rubies to expand your valley more quickly but so far I haven't done that.
In the game you can decorate the valley and the moomin house. By decorating you get more items you can use to expand the valley and decorate more. You can also visit Moomin's friends which gives you more shells, party items and characters for your valley.
Over all the game is very cute and starts very quickly which kinda made me hooked after just a few minutes but it slows down significantly at the higher levels and becomes a bit more challenging. The activities the characters can do are well chosen and the animations are cute. If you like charming little mobile games this is definitely a good one.