what does the lust meter do?
The only thing I can confirm myself, is that it begins to affect your chance to hit in combat once it goes above 50.
It might affect the outcomes of certain scenes, or influence what choices are available in certain scenes. My co-dev is the one who writes the scenes, which is why I can't say for certain what is effected there.
Honestly most of the "gameplay" is WIP. Hunger, lust, size changes, leveling up, EXP, and the entire combat system are pretty bare right now. It's something I'll eventually get to, but my primary focus so far has been building and expanding the scripting language that my partner uses to write porn, so he can write even more porn and in different ways!