Thank you for your understanding! It's great to hear that you appreciate the serious and story-rich aspects of the game. Creating such an experience can indeed be challenging, especially for a first-time project with a new game engine. Kudos to you for diving into it!
Regarding the keycards, there are actually five key cards in the game. It seems you've already found the first one, which was behind you in the starting room. The second key card is located in a tiny room on the right side as you exit the first room. To progress further, you'll need to keep searching for the remaining three key cards.
Once you have all five key cards, you'll be able to come out of the facility. At that point, your objective will be to find twelve folders. Explore the surroundings thoroughly.
if you have more questions, don't hesitate to ask. Good luck, and I hope you enjoy the rest of the game!