Sounds to me like Tony & Friends in Kellogg's Land (
Link1,
Link2 - German page,
Link 3 with screenshots,
Link 4 - another German site) / Tony & Friends - New Adventures - Invasion in Kellogg's Land (
Link). The Amiga screenshots are the same as in the Ms-Dos version.
That game seems to be mostly known in Germany, might be even entirely in German too.