A little dull and slow, as far as these go. My 3 star rating here should be interpreted as a 5/10 rating. Like, it's not unplayable. But playing it just fills me with this feeling of strained patience. It's pretty, at least.
The upgrade that lets the auto-shooter shoot twice occasionally does cap at only doing it 80% of the time, though, rather than letting you achieve full-time double fire, which just feels in bad taste, honestly. Why? Why put that limit there? In summary, literally unplayable, I'm afraid.
Edit: Also, once to unlock the ability to corrupt structures, it tells you what the bonus will be once the structure is corrupted when you hover over the progress bar. But once it's corrupted, and that's an automatic process, you can no longer check what the bonus actually is. I believe it was +50% extra soul gain for the first two, the gate and the boulder, then it seems to be +100% for the bonsai, frogge statue, Gate 2 (the sequel). Then the well unlocks the well. Past that, Gate 3: The Threequel adds +100% soul gain again, and the shrine ends the game, so you probably won't have to worry about forgetting what that one does. But if you didn't see what something did or forgot, there you go!
(Also, the upgrade that says it scales with total souls collected actually scales with CURRENT souls held, be warned.)
Took me 49 minutes and 27 seconds to beat the game, for reference. I am filled with ennui, overall, at the end of it. Current version gets...a 5.5/10, I suppose but I don't recommend overall unless you're really quite bored.