So how old were Casey, Hun and the Turtles?

[neatoman]

So I noticed a continuity error.

When Hun burned down the Jones shop, he lacked scars, the Foot tattoo and dressed simpler, implying he was not in the service of the Foot yet or at least not as deep into it yet. He is also present when Shredder kills Yoshi looking more like he did in the series' regular time period, weird in itself as that's fifteen years later. Later we get an episode where the turtles as children meet Casey, who looks more or less how he did at the time the store burned down.

Even if the explaination is that someone screwed up and used the older Hun design when it should have been the younger Hun design at Yoshi's murder, or that it should have the older Hun design at the sabotage instead of the young one, it still won't make any sense that Casey is not a teenager at least five years later.

So who do I blame or is there a way around this?