Ungrounded is a platformer about growing trees. You fall all the way down from the sun, and must plant trees to get back up to the sun. The trees, being trees, branch out wildly, and you can make some zany shapes to climb around in on your quest upwards.
Controls, and gameplay, are pretty simple. You are a dot, you pick up red pixels and plant them to grow trees. Platform your way up, find more seeds, keep planting and keep going. Reach the sun and you win. There is an emergency ghost mode if you need help getting through the branches... but the key to press (space) didn't actually seem to do anything for me, so I found myself having to do things the hard way and avoid getting stuck.
The joy of the game comes from the various patterns your trees make as you go up. The trees slightly mutate each generation, so with a bit of creativity you could make some gorgeous patterns. The two concerns here are that the main playerspace is a bit narrow. There's plenty of space to go up, but not very much room left-to-right, so you're always going to be making some kind of tower. I also got a fair amount of slowdown once a modest amount of tree is visible on-screen, and it didn't take much to start lagging. I'm willing to chalk this up to either the Linux version, or just my computer not being adequately beefy... although I wouldn't expect a game like this to necessarily need beef.
Complications aside, Ungrounded is a relaxing little romp. I don't know if I'd have paid for it, but as part of the bundle, sure thing.
I enjoyed it. Ungrounded is a good game.