Whoa, you can type without looking at the keyboard? That's impressive.

Literal

Huh, keyboard not-looking [means-で] characters can-type [explanatory-んだ]. Amazing [feminine-わ][confirmation-ねー].

見ないで 'without looking' uses the negative て-form to express manner. 打てる is the potential form of 打つ 'to hit/type.' スゴイ in katakana adds emphasis (normally すごい or 凄い). わねー with the elongated ー is a relaxed feminine exclamation of admiration.