Hope you make a better version! few things to note..
infinite resurrection makes the health stat a waste of gold. maybe give the player 10 lives Or make him lose 2 random stat points upon death. something to make the health stat worth dumping gold on besides saving a few seconds as catman catches his breath.
side note this also makes sword less valuable since you could leave it overnight you will always eventually get back to mining.
as others have said the imperceptible (if any) speed gains through that stat make it worthless to dump gold into as well. it should be a small gain but maybe 3x-4x what it is now :P
all of that said about the stats only pickaxe is truly worth having for the overnight idler with maybe 20 sword (or more if you want) which wont take you long to get. the bottom cave mimics are just as strong as lvl 1 that should change as well.
make an ultra expensive upgrade for gold and gems gained on hit. or 2 upgrades for that even.
make an armour upgrade to fend off those stronger mimics in the lower levels ;)