Warning to linux users: I bought this pack and three of the five games won't work (out of the box) on my 64-bit distro. Crayon Physics especially is encumbered with out-of-date 32-bit-only libraries. I've seen posts by people who got these to work, but it seems to involve a bit of work, and possibly replacing video drivers with 32-bit versions.
They may still release 64-bit builds for some of these, so I'd check before buying if you intend to only use linux 64-bit. The sale is open for several more days still.
"VVVVV" and "And Yet It Moves" worked fine for me but I was really after Crayon Physics and Hammerfight when I payed.