Making it to Level 5 takes about 10-15 minutes, but can be even quicker if you already have multiple friends playing the game (as you could visit their compounds and earn extra supplies without using your own energy). Just make sure to access Mafia Wars 2 through the in-game pop-up that should appear for you when logging into Empires & Allies to make sure your progress "syncs" back to your Home Island.
Once you've reached Level 5, come back to Empires & Allies (refreshing the game if necessary), and you'll see the following pop-up, alerting you to your prizes. Specifically, the Fighter Bundle contains three items: Air Strike, III, Poison Gas III and a Tactical Nuke. All three will pop into your inventory where you can choose to use them at the most advantageous time for you in battle.
Remember, it's likely that this promotion won't be around forever, and as these prizes can really help turn the tide for you in battle, there's no reason not to spend a few minutes trying out Mafia Wars 2, even if you have no intention of playing it again. Play the game once, and you'll unlock multiple prizes across tons of Zynga games, so what are you waiting for? Claim them all before it's too late!
Have you already received your Fighter Bundle in Empires & Allies, or do you simply have no desire to ever play Mafia Wars 2? Sound off in the comments.