I liked the setting and the menu screen felt rather polished!
The music could be a tad more eerie, perhaps a bit louder too. The shots barely felt like I was shooting and the ghosts could use some sound effects. Relying on the dark environment to see them was hard.
Visually, I liked the environment, though I thought the bins could be a bit more highlighted, I thought they would show up later, so I found the vending machine but had no ghost dust, kept on looking around through the map, until I returned to the original text message and tried the bins at the side. The map limits could also use some buildings instead of making the character just be blocked by an invisible barrier. The shots could use bigger projectiles 'cause the first time I shot I thought it did not work. It wasn't also clear if I actually hit the enemies, until they died.
The UI shouldn't go behind the map obstacles, it made some places too dangerous to go because I would have no idea about my situation.
The main character sprite was jittery, when moving continuously it sort of kept flickering. I don't know about Construct, but in Unity this usually happens when you try to move an object in the physics loop as well as the framerate loop. Also, the sprites could use some changes in the pivot point. Depending on the pose of the character, it goes slightly up or down. I noticed it mostly while going upwards in the beginning of the game, as soon as I stopped moving the character moved a bit downwards due to the sprite change.
Overall this is a nice shooter with the buying mechanics. Round 6 felt hard as hell, it was the farthest I managed to go!