It's just an old release... It has nothing to do with first games being avaible for free....
I am planning to buy First Decade by myself this summer.
Some of the games(If not multiple ones.) in the 1st decade set have timing problems in newer OSs.....meaning the games time limit counters go ultra fast. This makes it almost impossible to finish some levels.
(I forget what game I noticed this on, but it was a sort of return to pearl harbor map in one of the game's official campaigns, I think.)