Super fun!!! It had me playing for weeks. The gardener's backyard is a lot more OP than the other one letting you get a lot of worms buying all the upgrades and ending up with 20 mil artifact points, then getting a new permit and eventually crashing the game. A bug I found was having around 1 trillion digs per second but even after 5 minutes still having less than that for total feet dug. (see image) 
I think that the artifact sensor unlocked too late because after it unlocked, I already knew the shapes of most of the artifacts. I also found the zoning annoying once I unlocked it, it was digging so fast that when I tried adding a zone to dig up an artifact it was already dug up. Sorry for all the negative feedback, I hope you know that I really enjoyed (and still enjoy) your game, as a game dev I try to give helpful feedback instead of saying how much I like the game but sometimes I can seem too harsh.