Circuit doesn't look that bad to me, for a mass-manufactured product is a good starting point. Having said that, in standard form if it was a commercial product it'd probably fail EMC test. It would need to be developed a bit more.
I like the way they block the sale of the hex code for it. Prevents people from building them too easily. If someone is prepared to write the code for it, hopefully will be committed enough to realise how potentially lethally dangerous a circuit like this is for a home electronics project. There's no easy way to test it, if you connect a scope to it: bang!, if you develop the code with a PIC emulator: bang! if you touch it with soldering iron: bang! if you touch it: ouch! , or ouch!, bump! (as you fall to the ground unconscious)