Hey you need a balanced gamplay here. Okay, the cops kill me if i stumble them. But don't don't know about may existence and ignores me when i'm walking away? So here is the deal: Places to hide, garbages cans, closets and desks can be a choice. If this is not a deal, so consider a "suspicion mechanic" or just remove the stumble-killing script. Is very frustating. Oh, you need to put a leveled upgrade system and most important a assassination technique, where you can kill without spilling blood. Music can change when panic rises and... it is.
Good points at the games is the non linear patrol system, stylish visuals, music is nice, but get boring after some stages. last is a good stealth system (and game), but as i whrote before, lacks a concealment system.
Gameplay: 3 (good stealth, bad stumble choice, need concealment)
Sound: 4 (boring after some time)
Fun: 4,5 (Its good after all, ony frustating when stumble in the cop)
PS: Sorry my english.