第4代的特点：
支持单人模式及多人模式（最多4人）
支持局域网及互联网合作作战
Up to 4-player cooperative play!
Journey to 12 star systems — across weird and wonderful foreign galaxies.
Fight through 120 waves of invading chickens.
Discover 9 awesome weapons — plus a secret one!
Upgrade weapons through 11 power levels — and a supercharged 12th!
Collect 30 unique bonuses.
Acquire 15 medals — advance your chicken-hunting career.
Unlock 20 secret features.
Internet high score tables — compare yourself with people from all over the world!
Multiplayer — play on the same computer, over your LAN, or on the internet.
Over 20 minutes of original orchestral soundtrack.
