Not so much a review, hence posting it here, but just a recommendation. If you have RDR but haven't downloaded this pack yet, I strongly suggest you do. It's absolutely bloody brilliant.
For my money, RDR is already the best sandbox environment game out there, and quite possibly the best game I have ever played of any kind, but this addition just puts the cherry on the cake. It's brilliantly constructed, superbly executed, and very very funny. Hunting down sasquatches, zombie wolves etc, clearing graveyards that look like an audition for a Michael Jackson video, watching very funny old west characters getting their comeuppance as they are torn apart, and blowing a zombie's head off with a shot gun. What's not to like?
If you have a PS3 or 360, I cannot possibly recommend this highly enough.