To paraphrase the great Dr. Doofenshmirtz: If I had a nickel for every time I got unexpectedly hooked on a sci-fi yuri mystery hybrid visual novel/puzzle/rhythm game, I'd have two nickels. Which isn't a lot, but it's weird that it happened twice. While my first exposure to that niche within niches was the excellent (and free) vivid/stasis, I ended up losing far more of my weekend than I'd planned to In Falsus, a PC-exclusive genre fusion from Lowiro, the London/Tokyo-based (more on that later) indie outfit behind mobile and console rhythm hit Arcaea.

It is also the closest thing to perennial arcade sicko's pick Sound Voltex. A game played with six buttons and two analogue dials. You are not ready. I wasn't.

While this is a beefy game and I'd have to sink MANY more hours into it to give it a full review, my conclusion from my first eight hours or so is that this is a dangerously compelling game, a well-written visual novel, an engagingly tough puzzler AND a rhythm game that requires you to play both digital notes on the keyboard and follow an analogue side-track on the mouse. It's a lot to wrap your head around, but I reckon that even genre newbies will be able to squeak by thanks to generous accessibility options and a relatively tame Easy mode.

At part-way into In Falsus' second act, I've still got very few answer to many of the mysteries it has set up. Set in a near-future sci-fi world (although the calendar reads that it's past the year 10,000), everyone wears a Bind, a high-tech collar/mood-ring that displays the emotional state of the wearer and flashes an angry holographic warning if anyone speaks a lie, hence the title. Everyone knows what's true or not, unless they're posting on the internet or part of a protesting 'mute' subculture that refuses to speak, lest their words be processed by their Bind. Weirder still is the strange band of triangular geometry arcing through the sky, which people anxiously try to avoid thinking about. Normal stuff.

The story follows a group of five high-school girls, each from a different academy, who have been drafted into a bizarre government program, initially tasking them to unmask a local hacker group. They're a likeable (and very gay - if you like girls getting goofy over how pretty and cute each other are, this is for you) cadre, who all discover that they've all got the ability to freeze time and dive into a shared mental realm, able to read memories and alter the moods of those around them. And when this happens, the process plays out in the form of a rhythm game.

And (outside of an arcade mode where you can just play for fun and scores) this is where In Falsus turns from a casual VN into a rhythm sicko's dream. One built with the PC in mind. On one hand (literally), you've got six buttons to hit on standard and hold notes as they fall down six lanes. Simple enough. On the other hand (again, literal) you've got your mouse, which you've got to dance through sweeping paths and swipe by notes requiring a sharp left or right swing. And you have to do both at the same time. On easy mode, it's not too demanding. On Normal, it's like patting your head and rubbing your stomach at the same time. On Hard and above, you need to fully bifurcate your brain and process two streams of rapid-fire information simultaneously.

It's a lot, but I found it surprisingly easy to get up to speed on Normal difficulty, although Hard pushes me to my limits. The music is great too (coming from a lot of rhythm game regulars), so my only real complaints are that the leftmost and rightmost notes (by default played with left shift and space) aren't as visible as they could be, often sneaking up on me. It's a common gripe, which hopefully will be addressed soon. Being left-handed, I also struggled to find a comfortable button layout to hit all six keys at the same time, so used the free app X-Mouse Button Control to bind the leftmost and rightmost lanes to left and right mouse buttons, giving me just four regular keys to keep up with on keyboard.

But wait - there's more! This is a puzzle game, too! And with some light RPG elements as well. Each rhythm stage in the story mode has you in conflict with another character, who plays five cards that will 'attack' you through the song. You in turn play five to counter that and reduce damage, and you craft them through a remarkably intricate hexagonal tessellation puzzle. It's the slowest part of the game, rewarding increasingly complex solutions with tougher variants of each 'crafting' challenge, but I've found it a nice meditative way to cool off between tough music stages, and a space to process the plot beats before continuing with the next chapter.

I was also initially impressed at how coherent the game felt in English while still being accurate to the Japanese audio (based on the little spoken Japanese I know), but a little research into developers Lowiro revealed that they're a primarily UK-based outfit with a secondary office in Tokyo. As such, it seems likely that it was written as a bilingual release from the ground up, with a script originally penned in English but designed to be seamlessly voiced in Japanese. I'd be curious to hear from Japanese players how well the script flows in their language, but the English script is sharply written, with each of the five protagonists having their own distinct voice that shines through even when they're not speaking.

I feel like I've still got a long, long way to go until I roll credits on In Falsus, with the stakes of its story only being hinted nervously at so far, but I know I'm going to be sinking a lot more hours into this one. It's an interesting sci-fi mystery, an engaging puzzle game, and a rhythm game that could only exist on PC. And if you're a little intimidated by this or its price tag, check our our rhythm genre intro for a softer, cheaper place to start.

In Falsus is out now for £35/$40, with a 10% launch discount running until September 23rd.