Certainly, here are the main features of SantaPress as concise points:

1. Multiple Door Types: Open doors as single pages, modal windows, external links, or WooCommerce products.
2. Customizable Modals: Choose from automatic modal layouts or easily customize width, background, and visuals.
3. Interactive Quizzes: Add trivia to each door, and integrate with Contact Form 7 for follow-up actions.
4. Diverse Layouts: Eight beautiful layouts with 25 door images each, totaling 200 door images.
5. Personalized Calendars: Set the number of days and configure your calendar as needed. 
6. Hidden Mode: Initially hide the calendar, reveal it after a specific time or through custom triggers.
7. Festive Snowfall: Add a charming snowfall effect to your calendar.
8. Multi-Calendar Support: Use multiple calendars on your website.
9. Custom JavaScript: Add custom JavaScript for each door, such as tracking codes. 
10. Click Tracking: Monitor clicks for logged-out users and logged-in users (except administrators). 
11. Additional Options: Features like Preview mode, show/hide titles, shuffle doors, and disable past doors.
12. Custom CSS: Customize the appearance with your own CSS.
13. Responsive Design: Ensures your advent calendar looks great on all devices.
14. Compatibility: Works with WPMU and WPML, making it versatile and multilingual.
15. GDPR Compliant: Respects privacy by only tracking clicks without collecting IP addresses. 
16. Clean Code: The plugin code is clean and well-commented for easy modification.