It's a rogue-like RPG with a story (and lore), despite what the creator says there.
The cards at the bottom act as stats.
You can lose HP, and regain it. You use Passion and Reason, to fulfill tasks and quests.
You interact with NPCs which can either be adversaries, competitors, helpers, minions, teachers and even romantic partners (as much as that rolls in a lovecraftian game).
You go on adventures in all sorts of locations, that require skill checks and resources to overcome - and, if overcome, at the end yield a myriad of rewards, ranging from lore to useful items.
You can even craft, albeit in a very limited fashion, but with interesting consequences.
You can summon creatures to help you in your endavours.
And finally... you can dream, and explore the Mansus in all its glory.
It's an RPG.