Because of how much I enjoyed your entry last week, I had to play yours for this week, too. Props to you for going for a more ambitious project. I think you did a great job distilling Minecraft's sense of discovery, improvement, and achievement into a mini project.
I would have liked to see an exponential curve for upgrades. My whole playthrough I had been looking forward to absolutely destroying a 5x5 grid of blocks with a single click, and having my sight range expanded to like 50-100 blocks wide. (But then again, speed might then become a limiting factor, so maybe the equipment upgrades would need to implicitly upgrade speed). This to me is a more fitting way to reward the player and wouldn't have taken too much more effort; even a single tier at the very end of absolute godlike abilities would've sufficed!
Regardless, procedural terrain generation is no small feat to pull off within the time frame, and I commend you for that. What was your algorithm for ore clusters (maybe a pre-defined set of shapes with a set frequency per ore)? I'm assuming the caves were cellular automata?