Tajemství Oslího ostrova (often abbreviated as Too),[1] known in English as The Secret of Donkey Island,[2] is a 1994 Czech point-and-click adventure video game.

Jarek Kolář and Petr Vlček began working on the game in 1992 using school computers in the gymnasium of Slovanské náměstí in Brno where they were students.

Later that year, he founded Polička-based Vochozka Trading and released Tajemství Oslího ostrova as the publisher's debut title.

Visual assets from other adventure games were used, which, years later in 2018, caused the magazine Excalibur to express surprise that there were no licensing issues.

A paper-box edition was not available until November of the same year, at which point the second Pterodon Software game was released entitled 7 dní a 7 nocí.

[15] Gamepark felt the title was filled with "brilliant humor, pirate stories and beautiful cartoon graphics and great adventures".

[16] Gamesite thought that a big drawback to Tajemství Oslího ostrova was the lack of a musical score except in the opening credits.