Thanks for clearing that one up, Nikolai. Now it’s all clear to me.

Вы звезда!

the rule of negative direct objects governing the genitive (instead of the accusative) is a tad bit more complex than just that (not too much, though!).

the general rule is: in the negative, inanimate direct objects also govern (i.e. are placed in) the genitive case (remember that animates take genitive endings here anyways).

however, if the negation relates to the verb more than the noun (i.e. «i didn’t DO that» instead of «i didn’t do THAT») then this rule is often ignored (particularly in colloquial speech).

there are certain places where that genitive or accusative (one or the other) is REQUIRED:

if the object (noun) is STRONGLY negated then the genitive is required.

if the object is an abstract noun (e.g. любовь, слава, честь – love, glory, honor), something indefinite (i.e. not a specific instance of that noun) or the pronoun это, then the genitive is needed.

if the object is definite (i.e. if it would have a word like ‘the’ or ‘that’ before it in english) then the accusative is used.

a direct response to your observation:

note that while это (as a PRONOUN) takes the genitive, этот (an ADJECTIVE) is used to denote a specific (definite) noun, and so takes the accusative.

sorry for all of the CAPS, hope i helped you understand =)