Suggested fix (unconfirmed): Talk to Mary in the evening to trigger the option to go buy the dress. Continue advancing the days to find Igor later in the story.
Suggested fix (unconfirmed): Verify game files integrity via Steam and update your graphics drivers. If language localization is bugged, switch the game language back to English.
Suggested fix (unconfirmed): Press Shift+G while the game is loading to open the Ren'Py settings menu. Change the display settings until the visual output appears correctly.