X tier is parks you consider exceptional above most, if not all, others; I only placed a single park there. It should have been at the top, not sure why it did that.
This is based almost 100% on gut feeling, not revisiting any. I think it's fairly accurate but some could be raised or lowered a tier, and when I have time I'd like to gain some opinions on the parks I don't have a strong opinion on.
My line of thinking based largely on a quick judgment was that B tier parks ended up being generally average, good quality H2H parks. A tier parks had a bit of an edge over the run of the mill H2H park. S tier are among my favorites, with X being my favorite H2H park so far. C ended up being parks that are pretty good but might not have aged well. Same for D, but D also includes a few unfinished parks I feel are rather strong. F is largely just unfinished parks; they might be more competitive in a finished state (Snowdrift would become A tier, for example - Strong Narrative might make S).
I need to go through and look at a lot of these parks again to make a definitive tier list for me, but for gut feelings I think this came out pretty well.