The map has potential, but i’m going to go over some things that could use improvement.
FIRST: i recommend going to https://developer.valvesoftware.com/wiki/Team_Fortress_2_Sky_List
to get the exact lighting parameters for your skybox.
SECOND: Half-Life 2 textures don’t match the TF2 art style and look very out of place. Go down to the bar for keywords in hammer and type in “tf” without quotes
This will get rid of all textures that are not meant for Team Fortress.
THIRD: a good starting size for a staircase is 8hu high and 16hu deep (hu = hammer unit). yours look a bit too big.
FORTH: this area is completely out of player reach so use a nodraw texture for the sides of walls that players can’t see.
FIFTH: some of the lights look a bit too bright.
Best of luck in future endeavors.