Chrome 42+ disables NPAPI plugins like Unity3d plugin.
Copy and paste the following text into your browser: chrome://flags/#enable-npapi and enable the NPAPI plugin.
Or try another browser like Firefox
WW2-4U is a multiplayer shooter with a nice simple graphic-style. Join a server, choose your side and capture points for your team. Use your mouse to aim and shoot, arrow keys to move, shift to run, number keys 1-3 to switch weapons and R to reload.