That was another great video!
It's really rewarding to have such players, taking their task as seriously as you do. :)
I found very nice, and very interesting, what you say about the gun/mouse device.
Although there is an alternate key (Ctrl) for reloading (even because, as a Mac user, I'm very aware that not every mouse has the third button! :D) I think you got the point.
As I first designed the gun, my idea was to provide the player from the very beginning with a quite powerful weapon, able to put down in one shot most of the opponents (as long as they're still unaware of your presence); but also a clumsy one, noisy and slow to reload, in order to boost the empathy with the protagonist of this unsettling adventure.
I'm thinking to add, just in the casual mode, some kind of icon always on screen to check at first glance wether the rifle is loaded or not, without pulling out the weapon and looking for the small rectangle that appears on it.
Not everybody like my design choice, but at least I'm not the only one who like it! :D
About the old lady's potion, it "simply" doubles your stamina.
This is not a spoiler, since you're supposed to feel the effect inside your body; but the only immediate feedback is the stamina bar that suddenly empties before filling up again (the total length of the bar stays the same, unlike what happens in Dark Souls - for instance), and the old lady's words ("this potion will make you stronger") are a bit vague.
I will make them more explicit in the next release, because a lot of players have been wondering about the effects of the potion without ever figuring them out.
Eventually, I can only recommend - once again - to talk with people in order to understand how to deal with the giant and where to find some oil for the lantern.
No more tips.
I guess at this point you're experienced enough to make it to the next ending! :D