Good news! 
We have the fix and it's now released! You have two options to fix it up.
Option A) Uninstall and Reinstall Poker
You can also uninstall your existing installation (remembering to remove all saved preferences),
download Poker again, and reinstall Telltale Texas Hold'em.
This makes for a new version number of poker: 3.0.1.9. The only fix being a prefs prop that sets the resolution to 800x600.
Option B) Replace your prefs.prop with a new one.
Download the attached ZIP file and replace your existing prefs.prop with your choice of either 800x600 or 1024x768 resolutions. You will need to rename the file to "prefs.prop" and overwrite your existing prefs.prop.