So, I have some thoughts on the combat...
Currently, the defense debuff from attacks seems a bit superfluous to me - in the sense that you're basically going to be at a minimum throughout most of the fight (with exceptions like bears and giant snakes) regardless of what you do, until there's only a couple of enemies left, at which point you've essentially won the battle already unless you're extremely unlucky. Using "Defensive Attack" is really the only ability that raises your defense that I'd consider when facing a mob, since it's still chipping away at them while offering you temporary protection. This is especially true because of the sheer number of enemies that have multiple attacks - with the larger orc fights, for instance, all the archers with their double attacks mean you're looking upwards of eleven attacks per round.
That said, I believe I understand the intent behind the mechanic; to recreate the feeling of a giantess overwhelmed by a mob of tiny nobodies, who win through sheer persistence and numbers. That individually, they're nothing, but there are a lot of them. To improve the mechanic, here's what I'd suggest instead: give a floor to enemy attack skills. Just add five guaranteed damage or so to each hit (less for multi-hit skills), so you still feel your hp being chipped away over time.
Alternately, change how the player's dedicated defensive skills work; rather than just improve your defense, they also protect you from debuffs for five rounds or so. Missing out on an attack would still hurt, but it would be worth considering.
Second, the critical rate being so high is rather unfun; the amount of damage they do is fine, but it still feels like the sheer number of attacks flying around more or less guarantees that you're going to be taking a crit or two each round - the only question is who's going to land it, and whether it will be a headache or a catastrophe.
That said, I believe I understand the intent behind the mechanic; you're big, you're not invincible, and if enough bothersome insects keep trying to sting you, eventually they're going to hit something soft. To preserve this feeling of the little guy getting lucky without making the player ragequit, here's what I'd suggest: double the player's starting hp. Since healing is reasonably limited, this won't hurt the balance of the game much - it just means that the player has a bit more buffer to work with, and deciding whether to heal mid-fight while risking another crit, or to instead push for the end of the battle becomes more of a strategic choice.
And while this isn't strictly combat, I'd also like to suggest including a dash option. The flying is fun and interesting, but there's a reason the industry moved away from including costs for faster movement in most genres - when the player just wants to get to the next point of interest on a map a bit more quickly, they don't want to wait for energy to recharge or burn items to recover. The player moves pretty slowly if they're not in the air, but it's no fun to show up to the next fight with only half your energy.
With regards to the rest of the game... I think you should include more descriptive text, honestly. It seems like you're focusing mainly on dialogue and pictures, but a bit of writing would go a long way to establishing the mood of various encounters.
The goblin at the start, for instance; including a description of how he seemed friendly and helpful to a naive, newly earthbound angel would help explain why the heck anyone would ever go with him - and talking about how he became increasingly shifty and nervous as you approached the forest would help ram home how yes, you were a complete idiot for falling for such an obvious trap.
It would also help explain some of the odder decisions you can make, like choosing to kill the guard or the couple you encounter, which... Well, I can see how that can be fetish fuel for a giantess game, but I can't really explain it in-context. I mean, they're just... There. Sure, I can squish them, but why? They're not doing anything to me! Explaining a couple of lines about what was going on in her head that leads to this option would go a long way - especially if it's tied to a variable so a more squish-happy angel gets more text in the future encouraging her to squish more humans. Who presumably object to being killed at random, and start to question whether they should put a bounty on her as well.
Ah, and lastly... I think you might want to consider using lower-resolution pictures for the game, if you're not going to increase the window size. With how small they are in-game, you're not going to see much of a quality reduction, and with nearly 600 pictures, saving even a small amount of space per-picture will lead to significant reductions in the game's file size. It's not a big deal now, but it will make things much more manageable as the game grows.