Finished the game.
Like the stealth game idea.
The enemy's AI looks like kind of buggy and unstable, but I think you can fix it afterwards if you want to. Maybe add some visiable indication to help player to figure out what state the enemy in or how far can they see will be better.
I'm not sure that I am using the right way to clear the level or not. But the levels make me feels that this would be a better game if I can use more than one clone. Maybe the only one concept didn't very fit to this game. Though I think you can handle that too afterwards if you want.
Overall, it's a nice little stealth game.
PS: There is a little game in my phone named "Sneak Ops". Maybe you will be interested in it^_^