I've just finished Blackshift. It's been in early access for ages, but now it's finally done.
Pick stuff up, push stuff, shoot stuff, try not to die. It's that sort of thing. There are 100 levels, arranged in an overworld that you have to explore. There are also hidden crystals in the levels that you can use to buy items to make things easier, but that's optional.
On top of that, there's a level editor, and you can browse and play user levels from within the game.
Give it a try if it sounds like your sort of thing! I'd love to hear what you think.