Mark of the Ninja — Perfect Stealth: No Kills, No Alerts, NewGame+ — lv2
The most important bit in this level is to get through it as fast as you can once you're inside the building.
Once the lights are back on, it becomes much harder to get through the areas safely and you get way more opportunities to screw up.
Mark of the Ninja is a stealth action game developed by Keli Entertainment, the creators of Shank and Shank 2.