Alchemy is a synth with additive and sampling granular-style methods, they are offering those apps as sort of a launcher, not as a replacement of the one on standard computers since it is still hard to render those additive, spectral sounds in realtime. so this one is something like some others did – a remote control for important parameters? no – it plays SOME sounds, lets you set ADSR envelopes and most important things. so it is meant to be a bridge to the main alchemy but also be able to play some sounds without external computers. and it HAS most of the functions of the big one. there is a pro upgrade and THAT lets you control things on the main computer
the app itself is free.