If you killing someone too slow, is it against the rules?
You also can't torture, so probably. Agreed it's a curious code of ethics. But the distinction is that "killing" another player just acts as a reset, while rape or torture are things they actually experience.
You can't change the appearance. This feature completely destroy the whole logic of gaming.
I don't think it "completely destroy(s) the whole logic of gaming," because the ability to participate in arbitrary fantastic scenarios itself is going to be a huge draw to players, even if you have to play as yourself. But I nonetheless agree (if Eternum were what it's claimed to be, which it isn't) that this is an odd restriction--wouldn't it be desirable to many people with disabilities to be able to play without them?
Eternum is the only game with no competition.
Someone doesn't remember Myst, I see. But surely "find the Gems of Doom" is competition? And, of course, all kinds of competitions take place within Eternum--so while Eternum itself doesn't have much of a competitive aspect if you aren't seeking one of the Gems, there are lots of smaller-scale competitions you can get into inside it.