tldr progression feels really slow. it's frustrating that for most of the game I feel like I'm just trying to catch up with my runners instead of being excited about new upgrades. Runners feel super undertuned.
As a few minor notes, I think it would be nice to be more clear about whats available in the demo and whats not. Buying the cyberdwarves upgrade and seeing buildings lead into the artillery hall is enticing until I spend all those resources only to find out they're not even implemented. Also had a small bug where I couldn't buy the gorilla or rhino upgrades for runners; seems like I have to click in a specific spot in the middle of the row for it to go through even if I have enough mythril and gold, whereas for any other upgrade I can just click anywhere vaguely in the row and it works. Tried clicking on the text itself and on the gold and mythril cost, but for some reason the sweet spot seems to be like an inch to the right of where the text ends.
I think prestige upgrades should make the first few levels a breeze. That's the slowest part of any incremental game and most prestiges let you basically skip it and get to the fun stuff where all the upgrades you can buy are. But here, the prestige upgrades are mostly for mid to late game stuff: making lasers and balistas stronger, unlocking more upgrades that require souls/mythril, and calamity-based triggers. Most of the prestige options available make the fast part of the game faster, but the slowest part of the game stays slow.
Even with max upgraded runners and max cyberdwarves, I can't come close to picking up everything. I see from other comments you want this to be a balance feature and I agree, but I think it's poorly implemented. For one, there are so many options for upgrading weapons and different types of weapons. It's fun and exciting to see all the ways I can clear stages and dens faster. There's only one option for collecting loot: the runners. I'm spending most of my gameplay worried about how I can get my runners up to speed with my weapons, which I didn't even invest into damage (only reload and gem chance), and feeling like I'm always behind rather than looking forward to better upgrades. I think there's only like one or two prestige upgrades that affect runners in a meaningful way; I was on t3 of prestige upgrades and couldn't wait to prestige again cuz I realized I really wanted to get the 300 ore overflow one, that's how necessary it felt. At this time, I feel punished for investing into weapons and it seems like putting everything into runners is the best strat, which is unfortunate cuz watching dwarves pick up ores is not nearly as exciting as watching my weapons mine them. Even then, having max upgrades on runners doesn't ever get me to a point where I'm collecting more than I mine. It feels bad when I have all artifacts and I'm still softlocked cuz having 25 runners means the next one is almost 200k gold for an increase I don't even know will fix my collection problem considering the jump from 20-25 didn't fix it in the first place. For weapons I can get more scientists to mitigate the cost of upgrades, but there's nothing to lower the cost of dwarves.
It's also frustrating that yeeting the ores collide into each other, meaning they have to be picked up again. With max capacity this can take a long time, making me feel like I'm being punished for upgrading into it when it feels so necessary early game. Longer time means more risk of getting stunned, since weapons can send out boulders even when there's no dens. It would be great if there was like a precision upgrade that stopped weapons from doing this. With max stun resist, it only goes down by 50%, meaning still about 8 seconds of downtime AND still a risk of ores having to be picked up a third or even fourth time. I see you commented that you don't want to turn off ore collision, so maybe have them throw it with a higher base velocity so it usually hits the left side of the screen?
I would love if runners had higher base speed to begin with. The early game is so slow, and this feels worse when it looks like the game doesn't continue in the background when alt tabbed. Having more prestige upgrades to improve runners speed, capacity, and stun resist would be amazing.