Hey thanks for trying out the game! When you first enter the ventilation shafts, keep moving forwards and then take your first right, head towards the end and there'll be a spot where the vent cover is missing and you can drop into the first room.
Okay, yay! That was great, very fun playthrough. Everything is very intuitive and nicely sound designed, and the challenges were a good level of difficulty to keep me engaged for the playtime. Great entry!