The beauty of Ground Zeroes is that it can be played in whatever style you wish.
For me, this game has incredible depth and real immersion if played as a Stealth game (no reflex, weapons, infinite Magazine throws, hold-ups nor kills). You're more conscious of lights, camoflague/cover, sounds you make vs environmental sounds, distractions, enemy's positions, focus and attention, etc, etc.
I'm currently working on my no-CQC and 100% Stealth :)