Great idea and implementation. Basically no critique to the idea, but some - maybe rather subjective - to the implementation: I would've made the difference in different squares' drill times much more noticeable and/or show it via a numeric UI. At the moment, green definitely feels faster than every other color, but the difference between the others doesn't feel so certain.
Viewing post in Unclogging the Pipes jam comments
Thanks! A number or something more visible/eye-catching to show that different blocks break at different times makes sense, I originally conveyed that by reducing the opacity of blocks, but it would be good to know what's easy to break before you start drilling. Green is supposed to be the fastest, another thing I probably could do is make the time it takes to break other blocks larger, so there's less of a gap. Thanks for the feedback!