Okay, well my major upgrade is probably going to be to try and move to ActionScript 3.0, unless this is likely to make the project inaccessible to too many people (it shouldn't do). This will hopefully make setting up characters a bit easier, and remove the need to "poll" (constantly test a value) by using an events-system instead.
Additionally, current game-data such as Krystal's relevant stats, inventory, and relationship to various characters she's interacted with, will be kept in some structure, so that we can allow game-data to be saved easily.
My thinking for inventory is that it will be a small bar below Krystal's stats bar(s), and will display newest items normally. However, if you are interacting with a character, then relevant inventory items will be displayed, so you can quickly activate one. Likewise, if you wish to do something with a character, but an item is required, then the option will appear to choose to give that item (or one of several if relevant). Hovering the mouse over an item would display details on it, and a button on the bar would expand it to display all inventory. I like the idea of separating "quest" items that aren't usable normally, and general-purpose items that you can activate whenever you want.
The other thing I would like to discuss is if Krystal should have other stats than simply experience? My thinking is that experience will be the main factor for unlocking new scenes with characters, however she would have a new vitality stat. Some unlocked scenes may reduce this vitality, and if it lowers too much then Krystal will wake-up back at the nearest bed.
In order to avoid "damage", Krystal would need to train an endurance stat, perhaps by performing additional tasks for some characters, or finding appropriate items. The stats could also be named energy and stamina instead of vitality and endurance, if we continue with the assumption the player can't actually get Krystal killed.
My thinking then is that when fucking a character, Krystal's performance is measured by a mixture of damage she suffers, and how messy she is at the start. By performing well for characters you would gain favour, which may be required to unlock certain conversation topics, new scenes, or gain reward items that may be needed to proceed.
The stats/performance idea is purely an idea though, so I'd love thoughts on whether this would be a good idea, or perhaps just over-complicate things for the player.
Regarding Krystal's speed; since Krystal will hopefully use a single code "class" at all times (whereas currently character code needs to be copy/pasted into each instance), it would be easy to tweak her speed given suitable animations. It may even be another good idea for a trainable stat, representing the fact that she has just survived a high-speed crash only to get a few generous reptile rapings, so she's bound to be a bit slow to begin with