I just released a new version of the demo which stops the player for 20ms delay before digging into a new dirt block. I tried a number of different lengths and can confidently say that for me 50ms it just too long. I might try to go to 30ms, but wanted to start with a more modest change and get it out there, after which I can play with the higher delay and see how it goes. I hope this helps adress at least part of your concern about the controls, but I will frankly need to get more testing done by others before I can confidently tell. I might also try to center the option to turn down the game speed, or even make a slightly slower default.
To complement this change I also modified both Avalanche and The Pale Queen, so that they require less digging overall. The Pale Queen was also modified to remove the need to blow up the wall, and thus the eye bomb could be removed, and is once again introduced later in the game, as originally planned.
Oh, and singular "deformity" obviously.
Once again, thanks! Feedback makes a better game.