Good but needs polishing!
On at least 2 levels i have encountered now I cannot gain the "Kill X many" achievements because it simply doesn't spawn enough (within the second world area) and i've tried at least 10 times on each to no avail. Another issue i have is the timed achievements and the meta achievements for each; only gaining 25 souls for the highest one? Not 2500 not 250000, just 25. I assume that's you just not adding the correct amount of zeros but still. Polish.
I'll update to a 10 if some of these glaring issues are fixed! Otherwise great game!