I'm experiencing random crashes too, amongst the crashes that happen when clicking on the objectives button or going to the ingame menu anytime beyond Level 2, which makes it impossible to save without using the Quicksave function (which overrides your previous save).
I'm sorry, but i'm very disappointed in this release. Just like Grombart, this will definitely be the last impulse purchase I make from GOG. I can understand having to restrict particular content depending on the circumstances(such as the music in Rayman, or the Deeper Dungeons for DK1), but releasing a game that is unstable on modern day systems completely goes against the point of GOG in the first place.
If these problems aren't fixed sometime soon, i'm afraid i'm going to have to seek a refund, which honestly is something I really don't want to do.