I have actually played a one-shot of Spire years ago. Five sessions or so, I think, so I wouldn't necessarily say that the Heart is shorter.

From what I gather, Heart is focused on dungeon crawling, while the Spire is less combat-focused in general, and its main focus is working towards an anti-colonial revolution.

What I do like about Spire is, first and foremost, that it isn't focused on dungeon crawling, and allows for making characters that have nothing to do with combat in general. I also like the themes of the classes, the setting, some motifs (the Firebrand class has an ability called 'the Means of destruction', which I remembered on a recent reread).

However, the Spire does have things that I consider to be issues for myself. Or, rather, it has one significant issue that does bring the system down in my eyes: the way characters take stress feels kind of unavoidable, and there don't seem to be any sort of interesting ways to go around that. I can't make a clever plan, for example, to outplay a rival organisation in a way that avoids damage, for example, as I will just be hurt in some manner on anything short of a standard success - the dice will always be the sole arbiter of this, and not thoughtfulness.

And yeah, I used to be fairly deep when it came to TTRPGs.

Also, since my recent obsession with the system started, I did cook up a concept for a Masked spymaster character.