I think that there should be more than just a 2x2 airlock size like for example, 2x1, 3x3, 3x2, etc. and that there should be an option to fill your airlock tunnel or room with oxygen after you enter one side, then close the airlock behind you and the one in front of you to your base opens, it should fill it with oxygen like it would in real life. Thanks for taking the time to read this