Just finished alpha 7. Verdict: awesome. Great job!
In addition to the 20 or so feedbacks that I sent whilst playing, here are some general comments. I don't think there are any spoilers here but if you haven't finished the alpha yet, best go and do that before reading
* At some points I lost the mouse cursor. This is perhaps more to do with my eyesight than the colour of the crosshairs, but how about having a section in the options where one can recolour/resize the crosshairs? Similarly, you could allow the UI elements (the bars at the bottom) to be increased/decreased in size.
* I can't put a game down until I know it's complete. How about having a completion percentage somewhere showing, perhaps, how many quests have been completed (and, crucially, how many there are in total). Similarly, I have 31 silver feathers but I really want to know if I've found them all!
* Maybe this will be revealed later, but what's the deal with the feathers anyway? Other than increasing mana storage, do they/will they do anything? Will there be a reward for collecting a certain number? There should be!
* For the first 2/3 of the game I wanted to be able to change the game speed. In the end I got used to simply pausing when I needed time to think (ie. during a battle), but perhaps it would be useful to allow the player to change the speed during play, and to perhaps set a default speed during battle (if I could play battles at half speed this would give me more time to think and I wouldn't need to pause so much, but perhaps not everyone would like this. It should be a choice.)
* Master Tower Shield blocks the next five attacks, but it would be useful to see how many it has blocked so far (so I can tell how many more hits I can take before the spell wears off)
* As mentioned in a feedback message, I upgraded to master level on the 'Sanctuary' skill but never seemed to be able to use it. I assumed that it would be a new spell, but perhaps it just causes 'tower shield' to block projectiles as well as melee weapons? Either way this should be made clearer.
* It took me quite a while to figure out that by default I fire wood arrows which are unlimited, and not the steel arrows that I kept picking up. Maybe other people are quicker than me, but having an infinity sign where the number of arrows usually is would make this very clear!
* Maybe you're planning this, but you've got to have some puzzle involving the one book.
* I know you're going for adventure rather than puzzle, but even so I found the puzzles too easy. Myst-level is perhaps too hard, but you could make them a little more tricky. The organ puzzle, for example, was trivial once you found the book as the notes were simply spelled out. How about having the tune played out by some object so you have to figure out how to play it yourself? The sliding duck puzzle would have been better (IMO) if there wasn't a picture of the duck on the floor outside. Put it in a book somewhere (the biggish book of monsters?) so the player has to use some intelligence to figure it out! Similarly, the rotating labyrinth was pretty easy. Also, I quite like puzzles where you need to play with a pencil and paper to note things down and use them later. Perhaps some players would find this difficult or irritating, but there will always be walkthroughs online where they can go if they're really stuck (or build walkthroughs in to the game if a player doesn't seem to be making progress on a particular puzzle). If you'd rather that the focus was story and adventure rather than puzzle, then fair enough. This is just me describing my ideal game here
* I never finished the Fizz/Buzz quest because I couldn't find Buzz to talk to him after completing the dungeon. I've left and returned several times and tried walking out from the depths of the dungeon but I can't find him anywhere, so the quest remains unfinished. Not sure what I can do to make him appear.
* For the record, I played quite thoroughly (checking every nook and cranny, reading all the books, trying to find all the feathers) and my final save file reports a play time of 5h38min.
Most of this is nitpicking, by the way. It really is a brilliant game and I can't wait for the next (final?) release! I'm really, really impressed with what you've achieved here. How can two people create all this?!
Finally, if you have any specific questions about my experience please ask ASAP while it's all still fresh!