I'd go more into Dennis's part in The Cinematographer Project since I actually have the DVD but I just don't have access at the moment. So I will mention his crazy back noseblunt TWS cover at 3rd and Army, which involved coming in super fast to get all the way around the curve. Managing that significant decrease in speed through the curved noseblunt is also pretty wild to think of, but Dennis would be the guy to handle it.
Taking a look at his shared part with Zered Bassett in Skate More, Dennis's first and last lines gain speed by going downhill (at 1:04 and 3:16 respectively) and both stand out as a "speed demon's" kind of line, especially with his ability to keep his composure long enough on the last line for that final 50-50.
In his Pushing San Francisco feature for Real Skateboards above, just about every single clip is fast. Now the camera work and effects certainly help build that feeling of traveling at some high speeds, but only so much can come from videography to achieve that vibe of flying by on every trick. The two lines starting at 1:19 in particular showcase some awesome flatground tricks and just messing around in the streets all while zooming along.
For Dennis's shoe, he was basically given a new part in Adidas Euro Lines, which was a very welcome surprise. Again, he's skating super fast. Just like at 1:08 when Dennis plows through one 50-50 only to grind some more and gap out into the street. Watching him sprint and push at 2:03 is a pleasure in itself, even if it's just to get on top of the huge bank. Most people will climb to the top of the bank to start or just ask for a convenient tow-in, but Dennis does it the old-fashioned way through some heavy leg work for a more rewarding experience for us viewers.
In Since Day One (remixed), he uses his speed rather well in DC at 0:35 to tre flip up onto the ledge and then nollie frontside flip the gap. The double ollies at 1:04 must take a lot to just hold onto the speed to jump out to the street, and what's even cooler is that the clip is followed up by the 3-up-3-down spot where Dennis frontside 360's WAY OUT beyond the 3 stair just because of how fast he's going. And then at 2:35, Dennis claims the throne of 3rd and Army with 3 more sick lines to add onto his already impressive resume at the spot; the last line of 3 tight tricks and no pushes makes me smile every time.
And finally, in my personal favorite part from Dennis, Diagonal, the first downhill SF kickflip still in black and white sets the tone of the rest of the part to display some great speed. Dennis comes in hot for the two lines at 0:41 at some pretty well known spots. At 1:07, after pushing a bit, he quickly ollies down to set up for the back tail on the ledge and somehow seems to gain speed on that little jump down! Only Dennis... Seeing the ground fly by with the two lines at 2:06 and 2:39 is visually stunning, and I still wonder how Dennis manages to carve around after the back 180 in that second line because it looks like he always rolls out almost too far to come back up the stairs. Again, seeing Dennis physically run up at 3:26 for a huge frontside ollie is very gratifying, and his final ollie in Barcelona over the bench and down the stairs at 3:33 is one of my favorite ollies of all time. (Which makes Gilbert's AWS ad that much crazier.)