Greetings
So I tried out the miner thingy and although I loved the fighting of worms and zeds, I have a little feedback on the system and the gem system in particular as well...
So first up, my armour was all steel so I was ready defensively and my gun was a blue MG4 with normal 7.62 rounds plus a sawbat for melee, so I thought I was probably ready offensively. But turns out I may have been wrong about that...
The worms: These guys seem to have a huge amount of health, as it would take me 10 to 20 shots to their face to send them down. I think those little worms shouldn't take that many shots to bring down. Even the sawbat I had wasn't all too useful against them either, taking about 7 hits to finish just one of them off. In the first 2 rounds that wasn't so bad, since there was only 2 or 3 on the first wave about about 5 on the second wave. Third wave came about and I couldn't clear out all the worms before the boss ones started to show up, but most of the zombies were taken care of. I couldn't get them away from the miner.
The 4th round came and the boss worms came in. And they started to use that speed drain trickery that the Mortelentus boss uses... All I thought at that point was 'where is Morte?' I thought at first I had got a morte boss and was going around trying to find it before I worked out it was the boss ones doing it. The speed debuff trickery though just seems... Bullsh*t, for use of a better word? I honestly hate describing it as such because the whole concept of the miner and defending it is awesome, like really awesome and I know a lot of work went into it. And I'm all for doing more such events as it adds a new dimension to the game. It just seems you get debuffed unnecessarily even if you're far from the boss.
So after killing the boss worms (I think I had 4 or 5 of them) the other small worms had actually destroyed the miner by digging under it, I think. I was on flat ground and there was a clear hole where the miner had once been. 5 diamonds that took me about 50 ingame days to find were wasted... But I did get a decent batch of resources from the area from the dropped bag, but no way was it worth those 5 lost diamonds and all the ammo I used up on the enemies trying to defend it. It was fun, sure (until the speed debuff stuff started happening), but such a shame the machine got destroyed in the process. I think I used about 800 7.62 rounds total.
Overall I'd love to use it more, but given how much ammo you need to go through, it's just not worth it when I can auger the same amount up in less time. And I hate saying that because I thought the whole concept was amazing and really wish it was better balanced.
So maybe for the miner there could be a few changes to help the balance a little bit, which I think would make it more worthwhile to use. As honestly I'd love to use it more.
- Add a journal entry for how to build the miner. I had seen the wiki and video but having the journal entry in game would be really handy showing how to craft the components, extra things you need like a generator and a failure relay, and how to set it up.
- Small worms could have less HP - about 1/2 to 1/3 of its current HP. The boss one, not a problem as it's a boss and I'd happily say you could even double or triple it to make up for the lost HP of the small worms.
- The debuff on the boss worm should apply only if it can get close to you. I was over 10 blocks away from it sometimes and getting debuffed by it, which seems a little excessive.
- If the miner can be destroyed so easily, I have an either/or type situation, both of which would work I think:
Either: Make the miner use no diamonds in construction of the drill head (auger doesn't need diamonds in the blade, so...), and switch the control box to use a power core in its recipe. This would keep it at relatively the same point in the game (gamestage around 900-1000 when you have chances of getting power cores from bosses during horde night). That way if the thing is destroyed, you don't have to wait another 50 days to get it back. And the power core can be crafted if you power up the plant so would encourage its use more.
Or: Keep the cost of the miner the same with diamonds, but allow it to have up to 30 blocks placed around it to help defend it. That makes it possible to add 2 layers around roughly (thus requiring more setup, which is a cool thing and encourages design ideas) and gives you a little time to combat the worms, or add some shotgun turrets to take care of zombies whilst you take care of other things. The failure relay is another point that they can attack so being able to defend that also would be helpful too.
Now for the gem system... After killing the boss worms one of them had some gems on him. So I did get some rare things! That was good. However, both of them got destroyed when I tried to add them into the item slots to test them out. Whilst I was working out how to do this I noticed a few things...
Some items can't equip gems that would be really good to add. For example the saw bat can't equip gems when the spiked club can. The same with power tools - I'd love to be able to equip gems to those power tools as that would make them even more useful.
After placing a gem in a steel pickaxe, the first time it worked. I did a side by side comparison and it was a cool buff to block damage. I took it out and tried to place it in an auger, no dice as it couldn't be added. But, when I placed it inside the pickaxe again, the very same one, it got destroyed. So my gems were also taken... And that left me very sour

After losing both 5 diamonds and 2 rare gems, I put the idea of using the miner or gems out of my mind for the foreseeable future.
But, there you have some feedback, my musings, ideas and frustrations

I thought I'd tell you about the experience so you can maybe use this feedback in future versions of the mod. Still my favourite mod, though.