Looking like the work of a conclave of alien surrealists, Mantragora´s GUI consists of knobs, engine parts, tubes, an eyeball and a figure that looks like a candidate for the backing vocalist position in an android doo-wop band.
These last two features are not merely aesthetic adornments - they´re joystick controllers that can be clicked on and dragged about with your mouse. The overall impression is that this is a piece of cybernetic collage art rather than a musical instrument.
At its core, Mantragora is a 4-oscillator subtractive synth with three filters (two multimode, one all-pass and linked to the mod wheel). There´s also a trio of LFOs and the mysterious X-Tone generator. All oscillators offer basic FM functions, and the whole lot can be sent through reverb, phaser and chorus effects.
If you think that such a feature set would lend itself to spaced-out metallic textures, then you´re right on the money. A walk through the presets reveals lots of chrome-plated pads and oxidized sweeps that would be right at home on the soundtrack to a B-grade science fiction flick. Mantragora would be ideal for creating the theme music for an army of giant, irradiated insects. It might not be your first choice for a romantic ballad, though.
Mantragora isn´t for everyone by any stretch of the imagination, but if your music leans towards industrial soundscapes, you might find it to be just the thing. We crashed the standalone version once, but had no other issues with it.