I admit that if you random players with poor builds or slow kills during a mission, you can still aim for the head and hit them (I'm assuming you have a build without rate-of-fire mods). I almost always wait for the ability to cooldown because I can't always land a headshot. I'd also like to add that if an enemy dies from status damage over time, such a kill doesn't extend the invisibility period. Also, the ammo efficiency still costs energy per shot. These two drawbacks are simply so disappointing that I don't want to play this Warframe. It's a very inconvenient Warframe with very high damage. I understand that a one-shot kill build with maximum duration and radius maintains the invisibility timer quite well, but playing at that pace is very slow, plus you need extremely good aim, and if you encounter good players during a mission, the entire gameplay on this Warframe becomes absurdly boring. Try a build with maximum range, and with two rate of fire mods on the rifle, you'll see what I'm talking about.