Fridge / How To Drill Your Way Through Your Problems

• Scion's reaction when he manages to feel Lagann's power won't make sense unless you remember that the Entities actively seek to prevent the universe's death by entropy. Lagann's use of Spiral Power is actively draining the universe's resources, due to Awesomeness Is Volatile. An existence such as him threatens the Entities and their Purpose, of course Scion isn't going to take it well.
  • Spiral Power does not, in, fact, work like that. Rather, Spiral Energy is Anti-Entropic in nature, but overuse will lead to the Spiral Nemesis, otherwise known as the Big Crunch. In short, it won't end the universe by draining its resources, it'll just kill the universe with a supermassive black hole which consumes everything, which admittedly is still a pretty good reason to want to stop Spiral Power.
• At one point, Lagann mopes about fights finding him even when he doesn't want - basically capes throwing themselves at him. The shards actually seek him out because they need to grow in conflict, and Lagann weaponizes evolution.
• In the semi-canon omake and a forum on PHO, Kamina openly praises and encourages Lagann. When he realized he fell on Earth-Bet, Will decided to drag it kicking and screaming into the Shonen genre via his fighting spirit and bullheadedness. Frankly, what's there not to like about it for "Kick Reason to the Curb and Go Beyond the Impossible" Kamina?
• It may seem odd that Will was able to get his arm back to flesh-and-blood status in the middle of the fight with Lung, but there is precedent of such a thing in Gurren Lagann- Lordgenome, during the final battle, was able to regenerate his entire body using Spiral Power, and he was just a head. Interestingly, one of Lordgenome's contributions to that fight was to use his mastery of Spiral Power to build his personal Gunmen- Lazengan- out of nothing... which Will also did in the Lung fight (just with Gurren).
• Bakuda being nicer than her canon version makes a lot of sense. She spent her formative time as a parahuman under the thumb of Lung, who was to put it delicately, not a nice person. In this continuity, she was treated to Lung's hospitality, but was quickly rescued by Will and was treated with care, affection, and an outlet for her talents. It's practically pavlovian- her time under Lung doing evil involved her being tortured, while her time doing good involved a place to sleep, warm bed, warm food, and giant robots. And that's not even mentioning that he swept in and saved her from the foul dragon like some knight from legend...