This is how I picture you after this, uh, marathon. ;P

Actually, there's a patch for the Linux version.

(I'm honestly surprised because this is the first time I've ever seen the Linux release get a patch while the Windows one is a full redownload.)

It's more the "Linux got a patch but Windows didn't" that surprised me, given that both you and developers generally have had many more years to refine your skills and tooling for Windows patches.

News:
https://twitter.com/10tonsLtd/status/717700914275082240?cn=cmVwbHk%3D&refsrc=email

From MaGog's logs for 6 April (part 1 of 2):

NOTE! CHANGED FILE Baldur's Gate II: Enhanced Edition, downloadables, Windows installer, English (part 1 of 3) (setup_baldurs_gate2_enhanced_edition_2.0.0.1.exe ***TO*** setup_baldurs_gate2_enhanced_edition_2.1.0.3.exe; gog-1 ***TO*** 2.0.62.2 (gog-3); Thu, 16 Oct 2014 14:12:03 GMT ***TO*** Wed, 06 Apr 2016 10:10:03 GMT; 895,000 ***TO*** 995,872)

NOTE! CHANGED FILE Baldur's Gate II: Enhanced Edition, downloadables, Windows installer, English (part 2 of 3) (setup_baldurs_gate2_enhanced_edition_2.0.0.1-1.bin ***TO*** setup_baldurs_gate2_enhanced_edition_2.1.0.3-1.bin; gog-1 ***TO*** 2.0.62.2 (gog-3); Thu, 16 Oct 2014 14:17:03 GMT ***TO*** Wed, 06 Apr 2016 10:15:09 GMT; 1,565,112,704 ***TO*** 2,099,011,328)

NOTE! CHANGED FILE Baldur's Gate II: Enhanced Edition, downloadables, Windows installer, English (part 3 of 3) (setup_baldurs_gate2_enhanced_edition_2.0.0.1-2.bin ***TO*** setup_baldurs_gate2_enhanced_edition_2.1.0.3-2.bin; gog-1 ***TO*** 2.0.62.2 (gog-3); Thu, 16 Oct 2014 14:15:39 GMT ***TO*** Wed, 06 Apr 2016 10:10:20 GMT; 876,671,233 ***TO*** 145,286,382)

NOTE! REMOVED FILE Baldur's Gate II: Enhanced Edition, downloadables, Patch 1.3 (patch_baldurs_gate2_enhanced_edition_2.0.1.2.exe; ; Thu, 18 Dec 2014 16:23:32 GMT; 622,203,456)

NOTE! CHANGED FILE Baldur's Gate II: Enhanced Edition, downloadables, Mac OS X installer, English (baldur_s_gate_ii_enhanced_edition_2.1.0.6.dmg ***TO*** baldurs_gate_ii_enhanced_edition_2.2.0.8.dmg; gog-6 ***TO*** 2.0.62.2 (gog-8); Fri, 09 Jan 2015 14:48:33 GMT ***TO*** Wed, 06 Apr 2016 10:16:26 GMT; 2,313,942,772 ***TO*** 2,364,367,985)

NOTE! CHANGED FILE Baldur's Gate II: Enhanced Edition, downloadables, Linux installer, English (gog_baldur_s_gate_2_enhanced_edition_2.0.0.4.sh ***TO*** gog_baldur_s_gate_2_enhanced_edition_2.1.0.5.sh; gog-4 ***TO*** 2.0.62.2 (gog-5); Wed, 27 Jan 2016 10:19:20 GMT ***TO*** Wed, 06 Apr 2016 10:15:07 GMT; 2,301,497,781 ***TO*** 2,340,489,022)

NOTE! ADDED FILE Baldur's Gate II: Enhanced Edition, downloadables, Patch 2.0.62.2 [Linux] (patch_baldur_s_gate_2_enhanced_edition_2.0.1.5.sh; Wed, 06 Apr 2016 10:11:05 GMT; 229,602,987)

NOTE! CHANGED Baldur's Gate II: Enhanced Edition, changelog (http://www.an-ovel.com/downloads/chg/chg_1207666373.htm)
NOTE! ADD +++ Patch 2.0.62.2 (06 April 2016)
NOTE! ADD +++ The full, official release notes for the v2.0 update are attached at the bottom of this post. It details all of the changes to BG:EE, BGII:EE, and the Infinity Engine as a whole. It also includes a section that's just for modders talking about some of the new opcodes, triggers, and actions that the update adds, as well as a collection of guides to help UI enthusiasts get their feet wet tinkering with the new UI system. The document clocks in at just over 30 pages; you won't want to miss it.
NOTE! ADD +++ Compatibility with Baldur's Gate: Siege of Dragonspear expansion added.
NOTE! ADD +++ New Class: The Shaman
NOTE! ADD +++ New Cleric Kit: The Priest of Tyr
NOTE! ADD +++ Class Ability Tweak: Poison Weapon now scales with levels
NOTE! ADD +++ Item Tweak: Stupefier +1 has been adjusted to be more in line with the game's other equipment
NOTE! ADD +++ Spell Tweak: Enchanted Weapon now modifies the target's existing weapons
NOTE! ADD +++ Items can now be placed in the Off-Hand slot while ranged and two-handed weapons are equipped
NOTE! ADD +++ The User Interface has been overhauled with a new system
NOTE! ADD +++ Dozens of modder-friendly enhancements
NOTE! ADD +++ Hundreds of bug fixes
NOTE! ADD +++
NOTE! ADD +++ This is our biggest update ever, and it applies to both Baldur's Gate: Enhanced Edition and Baldur's Gate II: Enhanced Edition. We have a lot of improvements planned in the coming weeks and months as well; stay tuned for more information!
NOTE! ADD +++ Detailed patch notes are available here:
NOTE! ADD +++ https://items.gog.com/releasenotes_2_0.pdf

NOTE! CHANGED Baldur's Gate II: Enhanced Edition, file_size: 2.3 GB ***TO*** 2.1 GB





NOTE! CHANGED FILE Hammerwatch, downloadables, Windows installer, English (setup_hammerwatch_2.5.0.8.exe ***TO*** setup_hammerwatch_2.6.0.9.exe; ***TO*** 1.3.2 (gog-9); Tue, 23 Sep 2014 15:57:24 GMT ***TO*** Wed, 06 Apr 2016 10:58:15 GMT; 222,103,960 ***TO*** 232,139,088)

NOTE! CHANGED FILE Hammerwatch, downloadables, Mac OS X installer, English (hammerwatch_2.1.0.8.dmg ***TO*** hammerwatch_2.2.0.12.dmg; ***TO*** 1.3.2 (gog-12); Tue, 23 Sep 2014 12:22:11 GMT ***TO*** Wed, 06 Apr 2016 10:58:15 GMT; 166,278,214 ***TO*** 167,047,405)

NOTE! CHANGED FILE Hammerwatch, downloadables, Linux installer, English (gog_hammerwatch_2.0.0.6.sh ***TO*** gog_hammerwatch_2.1.0.7.sh; ***TO*** 1.3.2 (gog-7); Tue, 04 Aug 2015 19:21:35 GMT ***TO*** Wed, 06 Apr 2016 10:58:21 GMT; 135,613,200 ***TO*** 176,683,586)

NOTE! CHANGED Hammerwatch, changelog (http://www.an-ovel.com/downloads/chg/chg_1207659483.htm)
NOTE! ADD +++ Patch 1.3.2 (06 April 2016)
NOTE! ADD +++ Fixed multiple musics playing at the same time in custom games
NOTE! ADD +++ Several crash fixes
NOTE! ADD +++
NOTE! ADD +++ Patch 1.3.1 (06 April 2016)
NOTE! ADD +++ Misc:
NOTE! ADD +++ Local multiplayer game saves now show up in the multiplayer load menu instead of the singleplayer load menu
NOTE! ADD +++ Added slight directional effect to sound effects via panning (can be turned off in options)
NOTE! ADD +++ Auto-fire is a bit faster now
NOTE! ADD +++
NOTE! ADD +++ Technical:
NOTE! ADD +++ Replaced the OpenAL sound engine with FMOD
NOTE! ADD +++ Updated Mono on Linux/Mac version
NOTE! ADD +++
NOTE! ADD +++ Editor features:
NOTE! ADD +++ Sound effects can now be .ogg

NOTE! CHANGED Hammerwatch, file_size: 211 MB ***TO*** 221 MB

I was faster. :P
They're trying to fix an obscure bug.

From MaGog's logs for 6 April (part 2 of 2):

NOTE! Probably CHANGED FILE Moon Hunters, all_files, Windows installer, English, dl_ver: 1.0.2126 (gog-4) ***TO*** 1.0.2126_2 (gog-5)

NOTE! Probably CHANGED FILE Moon Hunters, all_files, Mac OS X installer, English, dl_ver: 1.0.2126 (gog-2) ***TO*** 1.0.2126_2 (gog-4)

NOTE! Probably CHANGED FILE Moon Hunters, all_files, Linux installer, English, dl_ver: 1.0.2126 (gog-1) ***TO*** 1.0.2126_2 (gog-2)

NOTE! CHANGED Moon Hunters, changelog (http://www.an-ovel.com/downloads/chg/chg_1452776767.htm)
NOTE! ADD +++ Patch 1.0.2126_2 (05th April 2016)
NOTE! ADD +++ Updated link for Port Forwarding instructions





NOTE! Probably CHANGED FILE Renowned Explorers: International Society, all_files, Windows installer, English, dl_ver: 277 (gog-20) ***TO*** 309 (gog-21)

NOTE! Probably REMOVED FILE Renowned Explorers: International Society, all_files, patch 267 (gog-17) [Windows] (dl_ver: 264 -> 267)

NOTE! Probably REMOVED FILE Renowned Explorers: International Society, all_files, patch 274 (gog-18) [Windows] (dl_ver: 267 -> 274)

NOTE! Probably ADDED FILE Renowned Explorers: International Society, all_files, Patch 309 (gog-21) [Windows], dl_ver: ***TO*** 277 -> 309

NOTE! Probably CHANGED FILE Renowned Explorers: International Society, all_files, Mac OS X installer, English, dl_ver: 277 (gog-19) ***TO*** 309 (gog-22)

NOTE! Probably CHANGED FILE Renowned Explorers: International Society, all_files, Linux installer, English, dl_ver: 277 (gog-17) ***TO*** 309 (gog-19)

NOTE! CHANGED Renowned Explorers: International Society, changelog (http://www.an-ovel.com/downloads/chg/chg_1435329098.htm)
NOTE! ADD +++ Patch 309 (06 April 2016)
NOTE! ADD +++ NEW:
NOTE! ADD +++ A new main menu with:
NOTE! ADD +++ New layout to make everything feel less crowded.
NOTE! ADD +++ A news feed to show news relevant to players.
NOTE! ADD +++ A reference to any Community Events, often the Weekly Challenge on our forums.
NOTE! ADD +++ Added incompatibility warnings (and solutions) for users with potentially incompatible hardware or drivers.
NOTE! ADD +++ Disabled metrics system
NOTE! ADD +++
NOTE! ADD +++ BALANCE:
NOTE! ADD +++ Yvonne has Charms instead of Sense of Humor
NOTE! ADD +++ Bia gains Defense instead of Formations
NOTE! ADD +++ Admiral Reis gives Military History instead of Formations
NOTE! ADD +++ Lute gives Storytelling instead of Astonishing
NOTE! ADD +++ Kwame no longer gets double helpers on high levels diplomat or quick thinker
NOTE! ADD +++
NOTE! ADD +++ FIXES:
NOTE! ADD +++ Pagans believe in the occult.
NOTE! ADD +++ The "truth in the occult" option gives tokens now.
NOTE! ADD +++ Oengus Crown treasure is BACK
NOTE! ADD +++ Fixed a bug in which Quick Thinkers had to be either really cool or really lame to run through the Meadow's Castle.
NOTE! ADD +++ Fixed the text of mood buffs.
NOTE! ADD +++ Fixed using the machine from machine vs. magic in the talking tree event.
NOTE! ADD +++ Fixed a place where the Monymusk treasure shouldn't be available but was.
NOTE! ADD +++
NOTE! ADD +++ OPTIMIZATION:
NOTE! ADD +++ Long audio files like music and ambient are now streaming to reduce memory load.
NOTE! ADD +++ More aggressive unloading of unneeded files to free up memory faster.
NOTE! ADD +++ Miscellaneous memory optimizations.

NOTE! CHANGED Renowned Explorers: International Society, file_size: 712 MB ***TO*** 1.1 GB





NOTE! CHANGED Baldur's Gate: Enhanced Edition, sys_req_win: Windows XP / Vista / 7 / 8 / 10, Processor: 1 GHZ, Memory: 512 MB RAM, Graphics: OpenGL 2.0 compatible, Hard Drive: 2.17 GB HD space, Sound: Windows Compatible ***TO*** Windows XP / Vista / 7 / 8 / 10, Processor: 1 GHZ, Memory: 512 MB RAM, Graphics: OpenGL 2.0 compatible, Hard Drive: 2.17 GB HD space, Sound: Windows Compatible, Keyboard & Mouse

[Similar for Mac and Linux]

Well, at least they're working on it.

I just hit reply on any of your messages so this message gets pointed out to you.

The setup executable of the new Baldur's Gate seems to be corrupt. After selecting the language used for the installer an error message pops up immediately. See picture.

Before you ask: No, it didn't get corrupted during download. That never happened to me with a download manager and on top of that the digital signature on the file checks out ok which is proof of a correct download. This should be corrected quickly before lots of people download a defective new version.