"Hacker" series is 75% off on GamersGate: Hacker Evolution Collection
(contains "Hacker Evolution" and "Hacker Evolution Untold") for 3.74 $/€ or 2.50 £. The individual games are also on sale, but the collection is cheaper. Hacker Evolution Duality
for 4.99 $/€ or 3.74 £.
I'm interested in the games, but know very little about the differences between them. Does it make sense to buy the Clollection _and_ Duality, or does Duality encompass most of the gameplay from the collection? What's the difference between the versions? Is duality worth 5 € (even at 75% off, that's a bit more than I usually pay for a game, and I usually pay this much only for AAA games, e.g. Mass Effect, Dead Space, Batman)? How big is the chance that games will appear in some Indie bundles where I can get them much cheaper?
Sorry for the barrage of questions, any help is appreciated. :)