The Exclusive Edition Extras (or EEE) for Gunpoint contain development prototypes, a making-of video and bonus music. This goes for the the same price as the Special Edition extras, and while you technically get more bang for your buck I'd say this is more for the real fans. Fortunately, I am a real fan.
The prototypes are interesting to behold, and something I would love to see more of from other games. The only other game I know of that did this is Uplink, and that game's bonus material was released for free
. They cover a range of points during development, some of which seem to have been used for game conferences and press showings. They're about 130 MB in size.
'The Making of Gunpoint' is a 297 MB MP4 file, high-quality but no subtitles. It's also interesting if you're a fan of developer remarks and commentary.
The bonus music is great - you could consider it as 'Inspired by Gunpoint', not to mention there are some audition & cut tracks as well. There are 28 files in all, 4 of which seem to lack metadata.
Specs for Gunpoint Exclusive Edition Music:
* Format: MP3
* Soundtrack length: 38m 29s
* Total size: 72.9 MB (including album art)
* 44100 Hz sample rate
* Bitrate varies: low 128 kpbs, high 252 kpbs
All of this is in your Gunpoint steamapps directory. You can right-click on a game in your Steam Library, select Properties>Local Files and click Browse Local Files to access it.
As for the secret beta list...I'm afraid I can't speak to that. It is, after all, secret.
Buy it on sale, because it's still pretty expensive for what it is.