yes, welcome to the forum :-)

Your screenshots also remind me of my first attempts with Gamestudio. I would say you got something good to build upon and I hope you will continue the good work. Here are some tips to help you:
1. Try to use different textures for the walls and the ceiling.
2. If you want to create a creepy horror atmosphere, put some columns in the room and set a lightmap right behind these columns. This will create some nice looking shadows that create a "dangerous" atmosphere.
3. Send me a PM if you like. I can give you some enemy models and weapons for your game, if you want them.

Welcome again, it's always nice to see new people here
Best regards
Rincewind