Ignis knowing how to stop Satandelos makes sense when you consider he spent years as a treasure hunter and likely has had to sabotage his fair share of robots and machines. With the Gigadelos units being sold as planetary defense weapons to various species, he likely had to contend with at least one in his exploits which gave him an idea on how to defeat them.
Ignis was playing what's heavily implied to be a gacha game during the Powered Dada's attack. Of course he would; gacha games get you hooked by offering limited time rewards. A perfect way to catch a chronic thief.
Mr. Shizuma being from the Neo FrontierUniverse explains a whole lot of things about his behavior:
How did he quickly figure out Kengo was Trigger and that he was The Chosen One? He'd know from Daigo and Tiga how that works.
How did he figure Kaiju were real in the past with nothing but a stone tablet? He had experience fighting Kaiju in the Neo Frontier Universe, so he figured out quickly what was happening in Trigger's Earth.
Why is his attack team, GUTS-Select, so similar to the original GUTS? He deliberately based them on his old team in his home universe.
Ultraman Ribut's human form attire, and his transformation pose pretty much reflect his (meta-wise) Malaysian origin, first debuting in Upin & Ipin. His attire heavily resembles Malay ethnic group's traditional dress called Baju Melayu. His transformation pose was inspired from silat, a traditional martial arts spread across South-East Asia, and the way he hold the Sparklence is actually how silat practitioners hold their tekpi (a trident with its handle shortened to form a kind of dagger).
After going over Ultraman Tiga, I realized that Trigger isn't just based on Tiga but the other Ultras that were with him in the Pyramid. Specifically the heads of Power Type and Glitter Eternity are at least partially based on theirs. Sky Type however is a small exaggeration of Tiga's, and Trigger's, own crest and ears.
This series established that Aboras and Banila have toxic bodily fluids and would pollute the environment if killed improperly. Whilst this seems like merely a justification for why the ancient people sealed them away instead of killing them, Tetsuo Kinjo's production notes for Ultraman listed the duo as being space monsters that somehow ended up on Earth, which explains that the pestilence their fluids would cause is likely due to foreign pathogens within their bodies, much like real-life invasive species.
Some of the numbering on the G.U.T.S Hyoer Keys from the toyline have more significance than might be expected.
Trigger is “U-01”, while Tiga is “U-10”, to indicate that they are similar, but different. On the same wavelength Dyna and Decker are “U-14” and “U-41” respectively.
Ultraman Zero is “U-15”, while Ultraseven is “U-30”, indicating Zero’s desire to be half the man his father is.
Nexus, Max and Mebius are “U-38, U-39 and U-40” respectively, matching with the years from the franchise’s start their shows premiered in.
The Dark Giant seen in Kengo's visions has similar eyes and color timer to Trigger, this along with several dialogue from the Dark Giants might mean he is Trigger's original evil form and once leader of the Dark Giants.
As revealed in the sixth episode, "One Hour Demon", 100 years before the series Hudram committed genocide in at least one planet: the Lishurians' homeworld, given that he awakened exactly at that time it brings the question as to how many planets did he decimate and races he drove into extinction before finally arriving on Earth when his teammates began to break free of their prisons.
The fact that Hudram somehow managed to snag a Gigadelos and transform it into the planet-killing weapon Satandelos shows that he either somehow found a way to the main series universe or at the very least got the hookup from someone who makes them in this universe.
Darrgon is shown to lift the 20,000-ton Zaragas with one finger whilst human-sized, which means his grip strength must be insane. How easy would it have been for him to accidentally snap Yuna in half like a toothpick whilst attempting to woo her?
Ignis (or is it Trigger Dark?) stole a prototype Sparklence, plus created Hyper Keys for Zaigorg and Horoboros. Imagine what he could do with those powers, in addition to what he received from Trigger Dark?
It's treated as a throwaway gag, but Marluru has the same Hate Plague-inducing red crystals his predecessor used to invade Earth. Why does he have them, and what exactly is he going to do with them? Even worse, Ignis is seen sniffing them, but we don't know if he stole them for his own use.
. His transformation pose was inspired from silat, a traditional martial arts spread across South-East Asia, and the way he hold the Sparklence is actually how silat practitioners hold their tekpi (a trident with its handle shortened to form a kind of dagger).