I have encountered a bug playing Frogatto on Ubuntu 10.04, using the 64 bit .deb provided in this thread:
Most of the time - though not always) - when text is seen on screen, only the first character (Edit: or a small number of characters at the beginning of the line) is displayed. This affects characters’ dialog lines, level names when entering a new level, and the point/money counters. Also see the attached screenshot.
In cases where I can move while the text is being displayed (such as with level names), the text will occasionally appear for fractions of a second while I walk.
I couldn’t reproduce the error on Windows XP, even using a savegame copied from the Ubuntu system.