I was wondering that too, though perhaps it has something to do with less libraries not being included in linux version maybe? (With my limited bandwidth I can only speculate that the windows version comes with more libraries)

I just made an experiment: I installed the "2.2.0" Windows version of Deponia 2 (don't own the GOG version of Deponia 1) using Wine - after installation, it took about 5.8 GB of disk space.

Then I installed "Patch 3.2" (f***ng GOG version number chaos!), and the result takes only 3.0 GB!

The Linux version is about 2.9 GB - almost the same.

So it's apparently not a Windows/Linux difference, but an "old version"/"new version difference" - Daedalic switched to another game engine that's apparently more memory-efficient...

Deponia for Linux always insists on Language: IT|EN for me, how can I change this?
I even redownloaded the whole stuff but no avail.

EDIT: OK, I clicked on language selection accidentally and didnot find it again afterwards as it is dull grey, it seems.
It's in the menu screen in the bottom right, next to the images of the different games (screenshot attached).

Thanks for the Linux port. I played Deponia 1, 2, 3 natively on Linux and it's working mostly OK. The only two problems I have encountered (tested with Deponia 3):
- it's forgetting the 'fullscreen settings', I need to uncheck and recheck the fullscreen option in the game settings and restart the game, after next boot it again starts in the windowed mode.
- it's also forgetting the 'click to open the inventory' setting. After successfully switching to the fullscreen, I have to re-enable the 'click to open the inventory'.

Edit:
It seems I found the source of the problem. Every time the in-game settings dialog is opened the resolution is reset to the 1920x1080, but my display has only 1366x768. To get the correct resolution I need to uncheck and re-check the 'fullscreen', and restart the game. Then it starts in the fullscreen and with the correct resolution (1366x768). But it also resets the 'click to open the inventory' to 'off'. If i change it back to 'on' it again resets the resolution to the 1920x1080 and on the next start (which I usually performs the next day so I wrongly assumed that it happened after the reboot) the game again starts with the wrong resolution. If I didn't use the 'click to open the inventory', I wouldn't notice this bug.

Edit2:
Another problem I have found is that the 'Art of Deponia' video is missing from the Linux installation. It's the videos/video.vv066 (for english) and videos/video.vv067 (for german or vice versa). Both video files have only 9506 bytes, i.e. there are just empty Matroska containers, so the video link is shown in the 'Bonus' menu, but if clicked, nothing plays. It's quite a long video (cca. 14 minutes), thus it probably required a lot of space. I guess that's what some reporters observed - the Linux version being much smaller than the original Windows version and I guess it's because of the missing video.

You probably long finished the game by now but if anyone have problem with resolution it can be solved by putting desired resolution in config file in .local/share/Daedalic and then changing file permission to read only. Changing any setting via options menu will overwrite the file so operation may need to be repeated or make sure to have all other things set correct before.