Yeah you had confused Chameleon for Invisibility. I picked up on this because I've played countless hours on the ES series so am excessively familiar with game breaking spells like Chameleon.
Chameleon would make you visible if you took any aggressive action, such as stealing or attacking, but invisibility was different. I think it was designed that you were only supposed to be at 20% invisibility, meaning you could be invisible if your enemy had a low enough awareness. But if you added several pieces with 20%, the effect was cumulative, so you could be completely invisible to every enemy. Closing down Oblivion gates was a cakewalk, when you could walk right up to the Sigil Stone without ever being attacked once...
About 4 hours into Skyrim now. Spending time doing some of the easier side quests as I get my character stronger.
As far as Oblivion went the spell code is as follows:
Chameleon = M% Chameleon for D seconds
Invisibility = Invisibility for D seconds
So Invisibility has always been an off/on switch, either the spell is active and 100% or it's not and off, and as soon as you pick a lock, cast a spell, observe an item, talk to a person, open a door, anything at all other than just move around, it's gone so there's no feasible way to steal/kill with Invisibility which is why they didn't give you an option of using Sigil Stones to enchant Invisibility on an item in Oblivion, learning from the uselessness of it from Morrowind. Chameleon on the other hand, always a degree of Chameleon that makes the person's appearance more transparent (I avoid the word "Invisibility" so as not to cause confusion) based on the viewing mob/NPC's level, detection strength, player's level, and of course the strength (%M) of Chameleon. Unfortunately I stopped using Chameleon after Morrowind because the spell was simply too much of a gamebreaker. It was easy to find enchanted Chameleon gear in Oblivion, plus usage of Sigil Stones, to keep one's self 100% Chameleon perpetually, which is just way too imba for my tastes. :/
hillbillywingsfan ugh those things beat my ass the first couple times I encountered them in some snow pit. I was still healing myself after a pretty rough encounter with a pit of bandits I accidentally ran into while trying to run toward the Winterhold College when I happened to fall into a pit with a Giant and those things are a huge pain to kill at level 1.
Speaking of levels, I just reached level 4 finally, wasn't even paying attention to the fact that I leveled so many skills on the way I could level a few times, then just trained a couple more when I got to Winterhold -- in the College they have a ton of trainers for magic-related skills.
If there's another complaint I might add, if I didn't already ***** about it, is the UI is excessively clunky and compared to Morrowind+Oblivion alone I find myself spending a great deal more time sifting through menus than I'm comfortable with. If there's a mod that changes this I will happily download it. No idea what the developers were thinking.