I missed the no hints acheievement for the hard main level because the cat was invisible, this doesn't feel fair

I've completed everything with no hints, but it doesn't show up.

has happened w other hidden cat games, but i have turned off all sounds on game, it doesnt work, with 1 game it turns on randomly even tho its still turned off

The location where the Wizard Cat/Student is supposed to be isn't there, it's just a blank wall. I've reloaded the game and restarted the level and clicked the area a bunch but it never shows up.

Ate to play on win 10 did not seem to find any problems. If there are problems with Normal mode on win 8.1: it is not passable, it writes about the arrival of a train with cats and problems with the menu begin (you can’t exit, restart, etc. Exit ONLY through a forced alt+f4 termination)....