Finished the game and also played some mine mode. Video:
It is a nice puzzle platformer. The mechanics were easy to understand and the graphics are appealing. For the puzzles, it felt strange that some of them had unwinnable states. Most puzzle platformers I have played have a design that lets the player continue the level without restarting if they mess up (with the exception when they die).Towards the end of the game the focus was more on action and precision than puzzles. Those are difficult to mix, which kind of gameplay are you looking for in the endgame?
Talking about precision, it is difficult to jump between two blocks. You can watch in the video how I struggled with that on the first screen.
The mining minigame is fun. It is much better to break crates than hit rocks, so without crates (or when crates are hidden behind rocks) there is little one can do. Also my computer got fried while playing (on browser).
Nice job!