I have done that of course... no dice.
It's some kind of permissions problem that can NOT be solved by Disk Utility and does not pertain to Botanicula specifically. It's an account issue.
It can be solved by running BatChmod
http://www.lagentesoft.com/batchmod/index.html, entering 755 octal permissions and ticking "Unlock", "Clear xattrs" and "Apply to enclosed folders and files". App runs then just fine. This applies to any app that refuses to run in this manner.