Cheers, and thanks for the feedback! I'll move the bomb to be more visible, tweak the order of the light upgrades and consider other changes.
I'll keep an eye on the download bug if it pops up for anyone else, it looks like a temporary itch/browser sort of issue.
The light upgrades are actually important to be able to find the ore and decide which direction to mine, it makes it more fun/profitable for sure. You can usually afford 1-2 upgrades every run, it's designed so that if you feel like you're missing something, you can go and grab it. E.g. can't find ore, grab more light, not mining fast enough, damage, not lasting long enough, battery. Damage and speed upgrades are important too, every couple of damage upgrades is usually a new breakpoint, e.g. for dirt/iron only: 40 -> 50 damage = 2 shot dirt, 50 -> 67 = 3 shot iron, 67->100 1 shot dirt and 2 shot iron (takes at least 6 mins to get to this point, realistically 10+ mins), and other weapons like plasma can help hit breakpoints too. I'll have another look over the numbers though.
Yep, runs go from 5s -> 30s in the demo, and in the full game it keeps getting longer, e.g. closer to the end you're at over 2 minutes + any extra collected from battery powerups.