System16 is just the name of the website, the system you're referring to is actually Namco System 1 hardware.
I know someone who was working on a Namco System 1 driver, but just sorta put it on the backburner - maybe some day it will get resurrected
In the meantime, the PCEngine / TG16 version of Splatterhouse works perfect in FBAlpha, give it a try.
best regards,
- dink