Do note that my thoughts in this review focus more on the first half to Chaotic Century that I had rewatched recently and do not include anything coming from the second half of the series, Guardian Force. With that said, onto the review:
Nostalgia can be quite the strange little thing at times. Sometimes, it can make you think of times that you believe were better than they are now. Other times, you may have rose-coloured glasses on how you believed certain things were when you were younger. The latter was the case for me when I seen Zoids: Chaotic Century ten years ago on Toonami. Just starting out my fandom in anime, I thought of it to be a decent mecha adventure series focused on the exploits of Van, Fiona and their pals on Planet Zi as they become entangled in war between two rival kingdoms and deal with the threat of a powerful legendary Zoid towards later in the series. It is still recognized to this day by older anime fans as the most memorable part of the Zoids franchise as it actually had an ongoing storyline and was seen as not so bland and merchandise-driven as other parts of the franchise like New Century Zero and Fuzors.
Coming back to it ten years later with more experience, exposure and some jadedness in viewing anime, I can't necessarily say Chaotic Century's aged too well with what I've been exposed to in the past decade. The series carries a blend of the typical cliches you could find within mecha and shounen action anime. Many characters within the series carry some sort of archetype typical of both approaches such as Van your typical young, energetic, adventurous, dense and naive male lead; Irvine the aloof and troublemaking partner with a heart of gold; Raven the psychotic and merciless renegade with his eyes set on the lead; and a nice number of antagonists who are cruel, merciless and desiring power for no particular reason other than the fact they are evil. There are some interesting characters that stuck out for me not being so bland like the mercenary pair of Rosso and Viola plus Major Schubaltz, but they're mostly supporting characters to the otherwise mostly bland lead characters. I don't even want to think of the number of times I felt the urge to whack Van atop the head for his "fight first, ask questions later" mentality he exhibited at many points throughout Zoids that you would expect of enough plucky leads from shounen action anime titles.
The major elements of the plot to Chaotic Century involve discovering the origins of Fiona's character and the ongoing tensions between the Guylos Empire and Helic Republic. The former does get a reasonable amount of build up as hints are dropped throughout much of the series regarding Fiona's origins and her possible connection to the mentioned powerful Zoid. The mentioned war, on the other hand, is a bit hollow with its plot thanks to the limited amount of fleshing out there was on both kingdoms and the reasons surrounding the war as it felt mostly like a backdrop for any reason for Van and his group to face their adventures and put up with Prozen's later manipulations. I'm all for seeing an anime focused on a fictional war. But if the series isn't even gonna bother properly exploring both sides and their reasons for engagement like the Gundam franchise and Legend of the Galactic Heroes, then I'm not gonna be as invested into it.
Visually, Chaotic Century's animation is on the standard side for a late 90s to early 2000s TV anime with its scenery and character designs, with the CG animated Zoids sticking out like a sore thumb compared to the hand-drawn character designs. There are a number of occasions where the series resorts to animation shortcuts with its battles such as reused frames and speed stripes. Still, some of the concepts for the Zoids when used in battle were quite unique such as how the Geno Saurer can make itself into a charged particle gun and the use of the E-Shields from Shield Ligers as a sort of battering ram.
Still though, I can't say Zoids: Chaotic Century was the show that I remembered it to be from a decade earlier thanks to my exposure to the common cliches it makes use of and having a nice number of hollow elements to its storyline. It does beat out the mentioned New Century Zero and Fuzors in that it doesn't feel as merchandise-driven with its series run and having an actual plot that it follows. But nostalgia for anime I seen years ago can only carry a series so far for me if it doesn't have anything that sticks out with it too strongly.