Giana Sisters: Twisted Dreams is true Kickstarter success story. What could have just been a lazy reboot of a notorious clone revealed itself as an utterly superb platformer, meticulously designed and gorgeously-realised, sporting an innovative reality shifting mechanic. It made me eat my words in our full review, and better yet, its DLC pack is included in Steam's £3.99 deal.
However, since Giana Sisters is no stranger to the occasional indie bundle, be sure to check your backlog. If you already own it then you can buy the DLC separately for 99p. Thanks to theg @ HUKD