Of course, the writers of the movie would be credited as "The Real Heroes Here." Who else would've written the opening titles? Alternatively, since Deadpool's greatest strength is his dialogue, of course the writers are the real heroes. They're the ones who made the movie funny.
Deadpool uses twin .50AE Desert Eagle Mark XIX magnum pistols. Widely regarded as a terrible handgun for a variety of reasons (loud, expensive, high recoil, difficult to conceal carry, ostentatious, finicky gas system, etc) using such a gun fits Deadpool's character really well; like him it's loud, brash, impractical, powerful (especially since he mainly goes for headshots, a .50AE is not a round a target will survive being shot in the head or body with), holds a manageable number of rounds (7+1 in the chamber, meaning less time spent loading magazines) and is intimidating as hell. Since he has superpowers he can also handle the immense recoil of such a gun one-handed with little problem. Before he became Deadpool he used a Para-Ordnance P14 .45, an M1911 variant that holds 14 rounds of .45 ACP which is a proven man-stopper.
Jeremy asking Wade for a big tip at first seems like simple greed. Then you realize that not ten seconds earlier, Wade pulled a gun on Mr. Merchant. Jeremy obviously thought he had just turned into a witness to armed robbery and/or murder, and asking for a big tip was his way of saying, "Look, just give me a huge tip, and I won't say a word."
Bob's association with HYDRA didn't get mentioned because they didn't have the rights from Marvel. Deadpool hasn't seen him since Jacksonville. Earlier in the film, Wade said Special Forces being in Jacksonville was classified. It being "classified" in-universe is a nice way of saying you don't have the rights to it in real life.
Deadpool gets frustrated after a long montage of questioning mooks about where "Francis" is, and getting no results. However, Francis only goes by "Ajax" and seems to hide his real name from others, so all of those mooks had no idea who Deadpool was talking about. Deadpool also tends to kill most of them so quickly that even if the few who might know who he's talking about are dead before they could say anything.
However, some of Francis'es employees heard the exchange, so it is possible that the word got out. Soldiers have a lot of down time, and gossip that juicy had to have made the rounds among 'Ajax'es' men, who all look ex-military. Of course, they also saw what Ajax did to Wade just for fun.
When Deadpool says "Cue the music," look (and listen) closely. He doesn't turn back and resume the Power Walk until the music actually does start back up. He didn't just say it as a formality.
During the Power Walk set to "X Gon Give It To Ya", Colossus and Negasonic Teenage Warhead seem to be suspiciously cooperative with the whole thing, even pausing nearly silently when they have to interrupt it, and resuming it without any signs of confusion or annoyance... because they're just characters in a film. They were going to do the power walk regardless because it's an established film trope, and they also were obligated to finish it since they'd started already. Deadpool just took advantage of its inevitability.
During the power walk, the music abruptly stops when Warhead notices that Deadpool doesn't have his ammo bag. When Deadpool cues the music back up, it's a little further into the song, almost implying that it had been playing that whole time and was just turned down.
Deadpool forces Blind Al to assemble his Ikea furniture while he's out hunting Ajax. Ikea instructions are pictures.
Negasonic Teenage Warhead nonchalantly throws her phone over her shoulder before charging Angel Dust. Seems out of character for the Phoneaholic Teenager to ditch her phone, right? Except shortly afterwards, we see that using her powers destroys her clothing... so it was going to get wrecked anyway. It's probably safer on the ground where she threw it (most cellphones can take a little fall without damage) than it would be anywhere near her. It is probably also why she keeps her hair short, since that can easily catch fire with her powers — it might even be burned off at that length every time.
In the comics, X-Men rebuff Deadpool every time he tries to join them. Why is it that in this movie, they are trying to recruit him? Well, in the movie Deadpool is actually a mutant, rather than just having Wolverine's Healing Factor like in the comics and given the only superbeings in this world are Mutants the X-Men can't just leave him unchecked since given his violent nature Deadpool's likely to put a strain on Human/Mutant relations.
Conversely, Comics!Deadpool is constantly trying to join the X-Men but Movie!Deadpool hates the idea of being an X-Man. Why? Well, he never wanted his powers, his entire quest is about getting turned back, the X-Men definitely won't let him continue his rampage, and given that he's aware of the alternate timelines, Deadpool clearly remembers the last time he was in an X-Men film.
Deadpool is knocking off and hunting a lot of people associated with a mutant trafficking ring. The X-Men probably realize that despite his methods, he is the good guy, and sending Colossus to recruit him is a way of trying to do damage control. If they knew of his other activities pre-Deadpool they'd see he's very much a good guy. In contrast, Wade in the comics was more amoral and Deadpool leaning less heroically/more ultimately neutral. They probably do know, since Colossus refers to him as Wade on the bridge - Wade Wilson is supposed to be dead, so Colossus knowing his name means he's familiar with at least part of Wade's backstory.
Most of the "stressors" Ajax applies to Wade are things like ice-water immersion, or being tenderized like a side of steak with great abs. In other words, stuff he probably encountered before in Special Forces training, in the field as a soldier, or as a mercenary. The Hypobaric Torture Chamber, not so much.
The reason why Negasonic Teenage Warhead is specifically Colossus's trainee? Because if she misfired while she was still learning to control her power, Colossus would be fine. This, in fact, becomes an Exploited Immunity: When NTS saves Colossus from getting garroted with rebar by Angel Dust, Colossus is right back up on his feet hurriedly carrying away both women from the collapsing half-broken ship.
Wade Wilson/Deadpool uses a lot of Gratuitous Spanish throughout the movie. It's very possible that during his Special Forces days, he learned Spanish as part of his training for his job.
Why was the entire Bad-Guy Bar so quick to jump to Weasel's defense when Angel Dust starts choking him? Well, besides the fact that he's a friendly, sociable guy, he (and his bar) are also a necessity for them. Sister Margaret's basically gives them a place to find work, and they know they can trust Weasel not to go spilling the secrets of his clientele. If Weasel were to die, they would have to find another place like that, and those are incredibly hard to find.
Possibly unintentional, but one of the ads for the movie (specifically one promoting the release on iTunes) censors Deadpool's "chimi-fucking-changas!" line to "Let's get out there and make a difference!" It's brilliant because, if you think about it, this movie has made a difference. Proving that a comic book movie like Deadpool can be made and be received warmly if it treats the source material with respect? Showing that comic book movies can still be profitable despite being slapped with an R-rating? Putting 20th Century Fox back in good light after duds like Deadpool's previous film appearance and their attempt at keeping film rights to certain properties? Take your pick.
Colossus being the mouthpiece for genuine superhero values could be seen as him merely reciting Professor Xavier's teachings, or a Take That! to The Cape, MCU's Captain America, just for making him really Russian.
When Colossus was originally developed for the comics, he was a straight sendup of Superman, from the farming background to the parents with traditional values to the primary color scheme costume to being a literal "man of steel". It's perhaps best shown here.
Colossus's monologue about being a hero starts with a statement that people think heroes have to be heroic all the time, to include while doing mundane things like getting out of bed and brushing your teeth. Instead, he says that heroes are normal people who, at the right moment, do the right thing. What was Colossus doing when we first see him in the film? Eating breakfast, like anyone would, and deciding to get involved in a dangerous situation, like many would decide not to do.
Technically, Wade was completely honest when he told Colossus that "That guy was already up there when I got here." After all, "here" as far as Deadpool was concerned, was beyond the sign, and the goon in question had already hit the sign before Deadpool and the SUV had rolled to a stop around where he was standing.
The only time Wade misses any of his shots while counting the bullets is when he's shooting at the motorcycle driver, who we later learn in Ajax. If you look closely while Deadpool is shooting at him, Francis is turning his head aside before each gunshot so they miss, which is a very subtle foreshadowing to the fact that Ajax has Super Reflexes.
When Deadpool says "Oh did I say that this was a love story, no, it's a horror movie", the style of the film becomes that of a "Monster Horror" film: Horrible disfiguring of Wade, then there's Ajax coming down the stairs to the basement to see what the noise is, then he fights the "Monster" (Wade) until he finally defeats the "Monster"...and gives the Monster a cheesy one liner. The sequence ends when...Wade crawls out of the ground, like a Monster that just wont die.
Prior to Wade's escape, Ajax has no objections to Angel chewing on a match. Later on, after Wade returns as Deadpool (and a long time after he caused Ajax's current base of operations to burn to the ground), a scene we see with Ajax and Angel has the former wordlessly remove the match from the latter's mouth, like a parent removing a cigarette from their kid's mouth. He probably put two and two together at some point, figuring that Wade had caused that fire and escaped by getting Angel's match from her. So now he's trying to prevent repeat incidents by getting her to quit the habit.
Colossus and Negasonic Teenage Warhead's kills are much more on the side of Bloodless Carnage, which would be odd for an R-Rated movie. What's even odder is that they don't fall victim to the Cluster F-Bomb, as most R-Rated features employ. Now remember that most X-Men movies are PG-13.
Some fans have complained about Colossus being portrayed as a bit of a goofball, including his embarrassment when Angel Dust loses her top, or puking at the sight of blood. However the story is being told to the audience byDeadpool. Colossus is behaving like that because it's how Wade sees him.
Wade is reckless and uncaring about his own safety (as he knows he can heal) but as soon as Angel gives the order for Ajax's mooks to start firing Wade runs at and tackles Negasonic behind cover, this shows that while he does rib her and is careless with himself he does get serious when she is in danger.
At the laundromat, Blind Al advises Wade to use seltzer water and lemon to wash blood out of clothing; "Or wear red, dumbass." She obviously can't see him, but she can easily tell that someone's standing next to the washers with something that reeks of blood, so an idiot rubbing blood-soaked clothing with a pre-treat pen is a reasonable conclusion.
Why would Wade find pegging uncomfortable? His cancer. Which happens to also be in his prostate.
Deadpool may have amazing regenerative powers, but there's no mention of him being immune to pain like Ajax is. Even when he's cracking jokes about taking multiple bullet wounds, breaking his limbs, or cutting off his own hand, he feels everything. On the other hand, he's been through so much crap he probably has a very high tolerance to pain by the time he puts on the suit. So... yay?
There's no telling how many mutant puppet soldiers have already been sold and are already committing the types of atrocities that Ajax describes. Deadpool would have been a WMD among mutants - a highly-trained unkillable engine of destruction.
Dopinder is pretty screwed when we last see him. He's just been in an accident, so there's going to be bystander and police attention to the fact that he's got a prisoner in his trunk(that probably got reduced to scrapple when the taxi was rear-ended) and a duffle bag full of illegal weapons on his passenger seat. Pinning the guns on Deadpool would be challenging, considering that all Dopinder has on him are his phone calls, and he did kidnap the guy for getting engaged to a woman he is pursuing. Oy.
Jossed, as he reappears in Deadpool 2
Remember the highway scene, the one that was copied from the test footage? Some of those cars were civilians. When Deadpool lands in the SUV, it causes a BMW to crash.
Wade wears a RENT t-shirt when talking with Vanessa about the horrific effects a terminal illness can wreak on a dying person and the loved ones left behind to care for them.
While it's hard if not impossible to ever feel bad about any injury Ajax receives, his ability and what it means for injuries is certainly horrifying. Ajax can't feel any pain from his injuries but that doesn't mean he's OK when he gets hurt. The damage is still done and he doesn't heal any faster than a normal person. That means that he could have a life threatening or even lethal injury and not know it until he keels over or drops dead. Great example in his second fight with Wade when Wade pins him through the leg with his sword. The position of the sword in Ajax's leg suggests that if it hasn't nicked it then it was at least dangerously close to Ajax's femoral artery.
Truth in Television. People who suffer from CIPA, the inability to feel pain, injure themselves without noticing often, including severe burns, broken limbs, and chewing through their own cheeks. They also don't realise when their bladders are full and need to set reminders so they don't pee themselves, a gag the film clearly wasted.
Meghan's situation is pretty scary if you think about it. What the hell was her stalker doing that made her desperate enough to hire a mercenary? How long has this been going on? Why did she resort to a place as shady as Sister Margaret's instead of calling the police? Did she feel like she couldn't go to them for some reason, or did she already try that, only for them to fail to help? She must have been genuinely scared for her safety, and extremely lucky that Wade decided to help her even though she had no money.