One more thing, why does Wolfram need to be the thing right after coal/iron quest-wise? Why not gold? It just creates a random gap where you have to rely on only digging for money which I don't really understand.
By the way, it feels like health has no point once you realize not to go so far that you actually take damage. The ore is never worth the repair cost so what's the point?
You could expand the game and make elevators (pay for them of course) for the different floors once you reach them. That way you could technically go on forever and never get frustrated with the depth.
After you buy all the upgrades just get a bunch of money, build enough buildings and keep skipping days. That last medium cheevo is a bitch if you actually buy explosives and play ever single day.
@Hunited- What exactly is the "twist" that you're referring to? Pretty generic TD just done well, don't just talk out your ass for the sake of talking.
 "Paladog"){kind=icon}
 "Utopian Mining"){kind=icon}
 "Nuclear Outrun"){kind=icon}
 "Clash: Rise of Heroes"){kind=icon}
 "Johnny Upgrade"){kind=icon}
 "Boom Town"){kind=icon}
 "Kingdom Rush"){kind=icon}
 "Immortal Souls: Dark Crusade"){kind=icon}
 "This is the Only Level 3"){kind=icon}
 "Edmus"){kind=icon}
 "Cardian"){kind=icon}
 "Tower of Greed"){kind=icon}
 "Epsilon"){kind=icon}
 "Defender's Quest (lengthy!) Demo"){kind=icon}