A "Narnia" Key

In front of you there was a small black box that you've just opened. On the top lid, "Narnia Key" was written in fancy golden letters. In the box there was a folded note the size of a credit card, and a pretty unassuming old time key, slightly smaller than a tea spoon and with a few teeth at the end of a round blade. It was however, very pretty and looked to be made with silver, small colored gemstones embedded around the head.

"So, its some sort of portal opener," Gary said as he picked up the key while you picked up the note. "I don't think I've seen anything with a keyhole like this before though, Adrian."

Gary is your friend and an old classmate from your computer science days. You're both done with school and are currently junior level IT-support troglodytes sharing a tiny apartment. Hopefully you'll climb the ranks within ten years and be able to pay down your student loans before you are both grey haired.

You give Gary a doubtful look. "If it opens portals to other dimensions, I suspect it'll find a way," you say as you pick the key out of Gary's hand. "Let's read the readme first," you flip open the note and start reading the text out loud.

Narnia key.
Use on a closed door. Put the key in keyhole vicinity, imagine what sort of alternative dimension you want to visit, turn the key half a turn counter-clockwise, open door to access new dimension. A short tunnel will appear.

Close your eyes once for a second while walking through the tunnel to adapt to the world you are travelling to. Don't close your eyes or close them or a second a second time to not be adapted.

To lessen anomalies and paradoxes, portal users will experience adaptations at random intervals. Strength and style of adaptation may vary depending on subconscious desires or conscious focus at the time of adaptation. first adaptation never happens before six hours after going through portal.

More details can be learned by opening a portal to "Default Tutorial Dimension."

"Okay..." Gary said and went silent for a moment. "So, should we test it out?" he pointed at your wardrobe door.

"Well, what sort of dimension do you think we should go to?" you say with more hesitation than Gary. "Personally I'd go safe with the tutorial dimension."