I've played hundreds of adventures (I kid you not). I really don't care if the game has graphics or not. All that matters is that it is a good 'game'.
It must be fair. It must be logical. It must have good puzzles. It must have a consistent and believable environment. It must be bug free. It must have good spelling, grammar, punctuation and capitalisation. It must have a good parser and a good vocabulary. It must understand any commands that would be reasonable in the context. And, more important than anything, it must be fun to play.
Oh, and if it has nice graphics, that's a bonus!