Hulk's end of episode catchphrase is a play on "Hulk Out"
Spider-Man' face is censored in the series when the mask is off due to the fact that this is a web show and the web-head has a Secret Identity.
Why did Tony create Mainframe as a gaming A.I. he could play against? He clearly misses Arsenal, who perished at the end of the Avengers Assemble episode "The Ultron Outbreak".
The Red Hulk Twins from "Days of Future Smash: The Tomorrow Smashers" may appear to be descendants of Red Hulk and She Hulk, but any hardcore Marvel fan would know that Betty Ross, Bruce Banner's love interest, becomes Red She Hulk at some point later on in the comics. It's entirely possible that Junior may not be the Hulk's only child from this alternate future.
It could also count as Foreshadowing, seeing as this show takes place in a long-running shared animated universe. While Hulk and the Agents of S.M.A.S.H. has ended, there is still a chance of Betty finally becoming Red She Hulk in another Marvel Animated Universe show like Avengers, Assemble!.
Given that Guardians of the Galaxy is set in the same universe and takes place before Hulk and the Agents of S.M.A.S.H., it makes even more sense why the Inhumans and the Guardians would take part in such a risky battle against the Kree-because they have a massive bone to pick with Ronan the Accuser: Ronan tried to force Black Bolt to destroy Attilan, and in addition to Ronan being a personal enemy to the Guardians, he killed Drax's family and killed hundreds of lives.
Think about it in the comics Skaar is Hulk's son so what could The Leader's greatest vengeance against the Hulk be? Having his son against him.
At the end of season one, the Agents of C.R.A.S.H. are still at large, and still have the belts that render them invisible to anyone who doesn't have gamma radiation in their system. This means they can do whatever they want, no matter how heinous, without anyone even noticing them.
Remember when Doctor Doom had given up on time travel at the end of the Avengers, Assemble!episode "Planet Doom"? In the first part of "Days of Future Smash" he apparently had proven it's plausibility again and created two belts that would allow him to travel through time. Meaning, Doom is one step away from conquering the planet and erasing any threat to him from history. Thus making him hopelessly unstoppable.
Even worse when you consider that if the belts are destroyed somehow, he has the intellect to simply create new versions. It's a never ending loop. Doom wins every time.
Doom mentioned the difficulty to get the needed minerals in Avengers Assemble so he might eventually give up for real like he seemed to do back then.