Very cool. Given that there are 9 forms, and Gotchard is clearly obsessed with 10, the 10th will be a power-up.
As for the two costumes shown: the red one is prettier, but also... more banal? In the trailer, he seemed to me a couple of times either Fourze or Drive. But everything needs to be seen in motion.

Slightly off topic, but it struck me that the scenes in the dark in Shin Kamen Rider were worse than in Faiz. I hope this is a shortcoming of Anno's directing, and not of the current era.

Yeah a few pieces are being reused, namely: gloves, scarf, the silver torso armour, the "fire" from the chestplate but not the rest of the chestplate. (The belt and card holder too ofc but those are always gonna be "permanant items" so not counting those ofc)... also kinda interestingly it seems like the undersuit for the torso is actually getting swapped out to change the line colours, as it seems to be a separate piece from the leg undersuit?

Imo my point still stands that these seem to be the most distinct full basic form changes we've had in a long time, if not ever

(I do think it's clever that they seem to be recontextuilizing what the fire is for different forms, this time it resembles the monster body for the skateboard card)

Anyways, even with all that stuff getting kept between forms I'd say a good 91% of rhe armour is different between the two forms we've seen so far, and that's wild compared to what we see in other shows (and tbh I think it's better to have a few key details stay to keep the chatacter recognizable between forms, the arrow eyes and scarf will mean the audience will always be able to recognize him as gotchard no matter how much they change the forms)

I still think the only "recent" (it's 6 years old omg) rider series to maybe have such drastically different armour between base forms is build, but I still think mix-and-match riders are kind of their own beast where things are just handled differently, so I think it's a bit of an apples and oranges there

Taka from Kotetsu Toys Japan Secret Base has already shared his impressions of Geats' film, including Gotchard's debut:
https://www.youtube.com/watch?v=gYqSOfN2HLE
Summing up what I've heard:
1) Hotaro is similar in personality to a mixture of Gentaro and Sougo (I guessed it!);
2) Alchemy is an important part of his personality (here Sh Ranger guessed);
3) In character and fighting style, he is also similar to Edward from Fullmetal Alchemist (Henshinzero assumed it);
4) Although Geats uses the Gotchard card, in the actual movie the new rider will only face Keilow. So in the crossover, he and Ace will get to know each other from scratch.

Some notes about the Gotchard Scene from the Geats movie, pieced together from a few different sources

And I'm guessing Gotchard will be like Jaden Yuki throughout the season.

Looks like Gotchard will turn out to be a "Pokemon" catcher rider. I wonder how many of the Chemys will be active off the map?

AppareSkateboard looks like Don Momotarou. Yo, Nippon ichi!

That makes sense. In addition to the arrows, Level 10 cards have the letter X as well. So much stuff with letter X lately, huh.

Looks like I was wrong about white cards being consumables, as I wouldn't recommend anybody eating their smartphones. They're hard and the batteries contain poisonous chemicals.

So, I guess white cards are more like basic inventory stuff in general, right? Like stuff people carry around, in contrast to purple vehicles which carry people around.

The main difference is that while Build has Best Matches, Gotchard only seems to have.... Matches. Like, for example, Build could use something like KumaDensha if he wanted, as there's no limit to mixing between organic and inorganic Full Bottles. But due to the symmetry of Gotchard's suits and the face-down sides of the Ride Chemy Cards, even if you alchemize 2 cards that add up to 10, they won't necessarily make a complete image in the GotcharDriver, like Kaiserbee and Burningnero doesn't but Gorillasensei and Burningnero does.

I think it would've been cool if each card had 2 different half-faces, but then people would have to actively think about which side of the GotcharDriver they need to insert it, so I guess I can understand why Toei opted for a simpler gimmick.

Funny to think they could have gotten Yu-Gi-Oh! GX's writer if they'd wanted to for this season, since he is a toku writer lol, he would have been a cool pick

GX was written by Junki Takegami, who many may know for writing: Megaranger, GoGo-V, Gaoranver, and Go-Onger

He was also a recurring writer on Tiga-Dyna-Gaia [TDG] era Ultraman, with a lot of great episodes under his belt. He also head wrote "Ultraman Neos" which Elemental Hero Neos is named after in GX fun fact (Also Chazz Priceton's Japanese name is pronounced Jun Manjome which is also possibly an ultra reference to the main character of Ultra Q.... also named Jun Manjome lol)

So would have been fun to see the toku writer who made a card game anime with toku references, write a toku with card game references

Still I'm excited to see Hasagawa and Hiroki's take on the series for Gotchard

I think limiting the form options makes sense in the context of the show's lore. In chemistry, and therefore in alchemy, not all substances, when mixed, give new ones, and something useful is rarely obtained at all. Plus, already from the point of view of the plot, after getting a super-form, the basic options quickly become unnecessary, otherwise at least there is a chance to see them all.
Besides, I still hope Gotchard tries to combine the wrong cards and we end up with a creepy deformed rider.