Hi,
We updated the game with the version 1.0. Now you are able to play on different maps, unlock achievements, drop the game item from Steam to sell it on the Steam market. We only had a bug to display this items on the game UI inventory so it will be fixed with update 2.0. You can visit the game page or download the game if you have it already to see all changes on the game.
New features will be available with the update 2.0. We'll bring the Steam Inventory Items display on the game Inventory UI function with the update 2.0.
Thank you for your patience.
Enjoy!