To clarify - the Red Alert addition to the pack is not
Red Alert 3. It's a stand-alone Red Alert 3 expansion pack called Red Alert 3: Uprising
! It's a lot of fun, but might contain some spoilers if you haven't already played Red Alert 3 through but intend to sometime!
If memory serves me, it contains 4 mini campaigns of about 3 missions each - quite possibly the final C&C single-player standalone game, considering the new C&C
is going to be a "Free to play" (pay to win) game, and EA has indicated they want to move this way with a lot of franchises. "Although some have incorrectly speculated this change meant the Generals sequel is no more, Electronic Arts has stated that Generals 2 will simply be the first in the new series of free-to-play games."
The bundle's going strong, currently at $8.5million - well ahead of the previous records of $5.1mil for the Humble THQ Bundle, and the Humble Indie Bundle V. The vast majority of it is going to charity, so get these classics for a steal while you still can!