In addition to goodies like a graphics toggle for lower-end devices and support for the code that will be displayed in Rovio's Super Bowl ad (the code will unlock another level), update 1.5.1 adds a fifth episode - "Ham 'Em High." It includes 30 new Wild West-themed levels, as well as 15 levels currently marked as "Coming Soon." Have a look:
Just like previous Angry Birds levels, Ham 'Em High is insanely addictive. Its graphics are good, and its gameplay is... oh, just update the damn app already. You can find its QR code and Market link below.
Update: The new SMS permission requirement is just a mistake, says Rovio. It will be fixed on Monday.