Just checked the bundle price for this series and as usual it makes no sense. It's $5.99 for all 4 games but I already own 3&4 and 1&2 cost .99 separately. Kind of a no brainer for the money.
Bundle prices take into account what you actually paid for the games you already own, not their current prices. For example, if you bought Sentinel: Mars Defense at release for $4.99 you should get a significant discount on the bundle (I think you might be able to complete it for just a buck), whereas if you got it for free during a sale you won't get any money off.
