AFAIK, it is written wholly in Assembler, by the same author that wrote BlizKick.
Although it is beta...i have not had any problems with it. I have used a variety of WHDLoad games, the 3 Amiga web-browsers, Miami, various Vapor products, ImageFX and ADPro, Directory Opus Magellan 5.82...and with no problems.
This is running on a straight A1200, AGA, Blizzard 1230Mk.IV with 32MB RAM, and a 4xEIDE'99 IDE adapter. No other hardware hacks. The only software "hacks" are FBlit, WBCtrl and SysPatch 2.2...these would be redundant if you were running an RTG display...
It works for me...but as i said...it is easy to revert back to your previous system, and un-install Blizkick/execv44...it may be worth a try...