I would like to see some improvements to the (otherwise awesome) Gog.com downloader and the installers in general.
Start with the downloader: there appears to be no way to launch an install directly from it... I still need to go to the download folder and manually launch them.
As for the installer:
1) it does not remember where I last installed a game, and always defaults to Program Files. Please let us set a default location instead (like C:\Games or whatever).
2) for older games, it does not recognise the newest version of DOSbox, and there is no way to install without Dosbox. So I must have multiple copies of Dosbox on my system :(

There's a grey Options button when you start up the installer. Like you, I overlooked it last time too lol

Wouldn't that require an entry in win register (or whatever it's called in english), or at a pre-defined location? It's just I can see people compaining about that... It COULD be mandatory thou (I know I would use it :D )

The downloader is still under development and is at the moment quite feature-less. I am certain the ability to launch installs from it is already on the list of desirable features.
It sounds like you are assuming that all installation files are using the same local installer config, which is not true. Each one is unique, so there is really no way for it to maintain a "default install location" other than the one that is included with the originally downloaded installation executable. That is why if you click on the Options button in the installer, you can change that location to suit your needs.
If you want to use the latest version of DOSBox, rather than the version that GOG has configured and tested the games with (hint, hint), I believe you just need to copy the DOSBox files from the new version over the ones in the game's installation directory.

Oh I know where it is, it's just a little pain to always need to use it...
@Fenixp & cogadh:
a registry entry would work, and would be all that is needed. Of course then they would need to update the installers to look at this entry for the user's preferred location.
@cogadh:
Right now I use a junction to replace the distributed version of Dosbox with the one I prefer to use, but it would be nice if either the installer would allow me to skip Dosbox (or ScummVM) completely, or at least somehow be made aware of newer versions.
The risk for using an unsupported version is one I am willing to take ;)