Defeat the end boss

Have 20 enemies killed by propelling airvents in the 'Secret Base' level

Kill a German soldier by dropping the churchbell on top of him in the 'Killing Fields' level

Defeat the German Commander Boss

Collect all weapons in the campaign.

Eat 50 cannoli

Kill 5 ball-and-chain zombies in mid air

Kill 75 enemies with headshots

Recovered the Mothership's Cooling Fan.

Complete the game on "Standard" or higher.

Defeat Stage 2 Nemesis.

Withstand the zombie siege.

Eliminate 3 House Players with a single Grenade