What a game. I'm just "starting" but it really good, perhaps a little lack of illustration.
But without futher spoiler, should i avoid either of the 3 corruptions if i don't want any "Bad Ending" ? (i kinda want the "best" one in my reach ^^")
None of the corruptions are evil! They're harmless below 20, and will unlock additional god-specific ending much later. In the meantime, getting above 20 will require you to make a conscious choice ingame. So don't worry about picking up a bit of incidental corruption, you can bang the succubi as much as you want without locking yourself into anything.
I will update the opening in a month or two, and we're starting to get lewd CGs and more custom backgrounds! Glad you're enjoying it so far!
Sarah's very existence proves that Aether and Nether can coexist - though figuring out how to master both will be difficult. Abyssal is, unfortunately, completely incompatible with anything else. Gods are jealous creatures.
For the time being, don't worry about screwing yourself - it's safe to learn magic and sleep with succubi/angels. Any major choices will be telegraphed!
I'm genuinely glad to hear that! I'm finishing up the upcoming mega-update now, should be out in a few days at worst.