There certainly are some very gruesome moments in this comic but not without cause. When you're telling the story of a mass murderer brought back to life by demonic forces with a talking smiley face pin then you can pretty much go in any direction. Nothing in this comic feels out of place or forced which is telling for something with as grandiose a story as this. It does have a very tongue in cheek comedic approach at times that didn't work for me but that is more personal taste than the comic not working. One thing I think the comic needs more of is the flashbacks to Ernie's past they're barely in the first two issues but they're some of the best storytelling aspects.
One thing I really like about the way this book is drawn is the influence in style. Evil Ernie has the ability to 'see' people's sins, often depicted on their forehead with demonic features added to the person. These sequences are what we would have seen if John Carpenter's They Live were a comic book. Artist Jason Craig does a good job of juggling the real, the fantasy, and the gore in the comic though sometimes the details get lost in some panels.
Evil Ernie starts off with a bang and doesn't worry too much about repeating itself. Though it stays true to the basics of the mythology it takes plenty of liberties that end make the comic more enjoyable. There are tons of zombie and vampire comics out there that you can read, and that's fine, but there's only one Evil Ernie and it's better than a lot of those.