Good start! I included it in my GameDevNetwork: The Big Festive Game Jam compilation video series, if you’d like to take a look. :)

After the first wave of enemies, anything happens? It would be nice if the gun fire had any kind of feedback for the player, like a shot blast. A searched all the place and didnt find anything too (just my death at the border of the map :). Texture and material from house looks nice. And the movement in the ladder could be faster (humble opinion). Keep going!
Edit: I was really surprised when i met the enemies. I looked at the horizon: - Oh, a city, let me see this houses before going there - and then BAM, the city is actualy a horde of enemies XD