Rating period ends soon. After that, there will be a long break, and I guess this is my last chance to share some of the things I've learned this time around.
(Actually, I knew all of this before, but I still made those mistakes, which means I didn't actually know, but that's not the point.)
Thanks to maintaining a proper Git repo this time, I can go back and record some gifs.
The main point to discuss here can be summarized as follows: no matter how obvious you think something is, make it even more obvious.
This is primarily about the tutorial.
Here is the tutorial in question, the one I had just a couple of hours before submission.

It looks pretty good. It tells you how to move and informs you that you need to shoot trees and pick up your arrow.

However, as a veteran developer, I knew you can never be too obvious!

I added a couple of extra arrows, but when I showed my game to a friend, he just started shooting at the dead trees. He didn't notice the BIG white arrow pointing at the target, and he wasn't the only one.

The scene was too noisy. Dead trees scattered around, and burning bonfires took players' attention away from the main task: shooting the big tree in the middle of the screen.
So, I basically had to remove all the dead trees, take out the bonfires, and add an extra animation to the arrow so it would flicker, making it more visible.
Thus, the final version is:

The changes are subtle; things have actually been removed from the game, but it made a huge difference.
However, the real issue, I suppose, (which I didn't actually fix) lies in the states of the trees. They look too similar; dead trees look sort of like live trees. Had I made them look like tree stumps, there would have been no problem in the first place.

So, that's another tiny lesson: game design is hard. :heart: