I have listed the areas which the hotel try get out of the deal:-

1) T&C clause "5.Weekend nights are designated as Friday, Saturday and/or Sunday nights only" - The second free night has to be a weekend night so either Saturday or Sunday night."

2) T&C Clause "6.This offer is valid for the expense of a standard Marriott guest room and room-related taxes only and does not apply to food, beverage, service charges, other taxes or expenses." Dinner is usually counted as food.

3) As you have noted this hotel is not taking part in the offer like 90%+ of all European Marriotts.

I would suggest calling the hotel before your stay, to check whether they will take the cert. Have you got any confirmation from the Paltinum Desk on this in the form of an email this will help with the hotel.

Tell us how it works out?

SM