A top 2 transformation game for me and a must-play for any transformation fan, or even fans of erotic world building
The crux of a successful MtF transformation game is what to do after the transformation. The erotic nature of an MtF transformation is the unexpectedness, at first maybe the reluctance, horror or surprise of the MC, followed by gradual acceptance and erotic exploration. But WHAT AFTER? For the 'Patreon subscribe' format that we live in, maybe the 'Version 1' of the game has the transformation and then the subsequent versions explore it, but more often than not your MC is a whore by Version 3... then what? Often, it just turns into a female POV game at best, or a repetition or an extreme drawn out tease at worst.
Transylvania's brilliance is its answer to this question in multiple ways, probably the smartest way I've seen. For one, your character is always on the brink of dying, and the only way to avoid it is by exploring the mystery, the world and MC and other people's powers. This is SMART. There is room for the MC to want to reject sex situations to try to find information. There is room for MC to want to accept sex situations if they think it will help them survive. There is a NECESESARY layer on top of the man -> woman -> slut dynamic that exists in every MtF game that can support many more interesting scenarios.
Then there's the 'mind haze' dynamic. The game inhabits the world of 'the occult' with monster, magic, and mind control all on the table. The game has a 'sanity' dynamic which corresponds to that world: The human mind of our MC cannot process the 'world of the occult', so there is a constant battle between his sanity and the bizarreness and powers of the world and people around him. Again, a smart layer on top of the usual MtF dynamic: a common theme of MtF games is quickly becoming a slut, but by explaining this dynamic (partially) through the world building AND positioning it against the MC's need to preserve some sanity to save their own lives, it maintains a reason for the game to keep going and write new scenarios.
Then there's just smart writing. With the aforementioned need to preserve your life and mind/identity constantly a theme, the game very gradually introduces plot elements and transformation elements enabled and established by the world building that challenge those two things in lewd ways. But the core themes are never forgotten.
Other good things: a good stats/clothes/journal setup, a logical game progression with a clever loop mechanic that doesn't punish experimenting, a great base for a game that you could imagine quite a bit more plot and transformation in future releases