I left off the chains that run from the two upright posts of the chassis to the Daemon's skull at the mouth of the barrel. This was a mistake. When I first received the bitz for the Hellcannon, I assumed that those chains were largely decorative, like the extra chains on the 40K Chaos Vehicle Accessory Sprue, and thus left them off. I didn't realize they served the practical function of adjusting the barrel's elevation. If anyone asks, I'll just say that the Chaos Dwarf servants of Tzeentch came up with some cunning internal mechanism instead.

I deliberately left the stoke hole doors off of the back of the Hellcannon. The skull design on the doors looked too Khornate for my tastes, and so I left the hatches off. I also clipped off the door hinges and filed those areas smooth.

There should be four pairs of wheels on the Hellcannon model. I mistakenly left off the second smallest set of wheels. At first, I thought they were an optional replacement for the second largest set of wheels. I think my model looks fine as it is, because with a normally assembled model, one can barely see the set of wheels that I left off. If you want to do a Slaanesh Hellcannon, six wheels would be perfect, as six is the sacred number of the Dark Prince. Tzeentch's number is nine, which like my number of wheels, is a multiple of three - so it kind of works. Okay, I'm stretching things. It was a snafu, pure and simple.

I left the large Chaos Stars off of the largest pair of wheels. This omission was deliberate. I liked the details inside the large wheels so much that I didn't want to cover them up with the big Chaos symbols. The Chaos stars are also fantastic bitz that I'm sure I'll use for a standard or some other conversion at a later time.

Because I left the Chaos star hubcaps off of the large wheels, I decided to attach the side restraining chains to the front of the Hellcannon chassis instead. This decision required me to file off the two rings that hang from the front ends of the chassis and attach my restraining chains to the single loops that remain.

I initially made a mistake when cleaning my crewmen. I thought the flames coming off the skull held by the Chaos Dwarf with the pliers were flash and immediately set about filing them down. About halfway through, I realized that I was filing down flames. I covered up my blunder by building up some exaggerated, serpentine flames to replace what I'd filed off.