Falling Sand is perfect for the casual gamer. You can search for “world of sand” too.
The basics are that you have a box with streams pouring down of different materials. They are sand, water, oil, and salt. You can draw with cera, wall, spout (water line) and plant.
It’s a bit like rock, paper, scissors. Oil breaks through cera and wall. Fire burns oil. Water puts out fire and turns sand to plant. Salt whittles the bouncy spikey thing.
There is no way to win exactly. You just play with it. I like to make water parks best. I also like to turn sandy islands into green hills.
You can’t really lose either. You could feed the bouncy spikey thing too much and it gets huge and you can’t break it down with salt and it fills the screen and you have to reload the page. Not that I’ve ever done anything like that.
ETA: the links all seem to be dead