Van Pelt: End of the line, Sonny Jim. Game's up. Start running. Alan:[pause] No. Van Pelt: Aren't you afraid? Alan:[nonchalantly] I'm terrified. But my father says you should always face what you're afraid of. Van Pelt: ...Good lad. You're finally acting like a man. [raises gun] Any last words? [Alan looks down and notices his game piece moving to the end of the board, after which the word "Jumanji" appears.] Alan: ...Jumanji. Van Pelt: Huh? Alan: JUMANJI!
Also, Alan got trapped in the jungle of Jumanji as a kid. Sarah stopped playing the game and thus Alan remained trapped for twenty-six years. And he survived. Most kids probably wouldn't last a few days or weeks in such a situation, but Alan adapted and proved himself a survivor.
Alan busting out his ancestor's Civil War saber to deal with the plants. "Sorry, Angus. Harvest time!"
Possibly when Judy tells Aunt Nora that she didn't lie when she found out the only reason they were able to get the house dirt cheap was because a supposed murder took place.
Aunt Nora: Alright that's it, I am sick and tired of your lies, young lady! You're grounded!
Judy: Fine! There's nowhere to go in this stupid town anyway! And just for your information: that wasn't a lie!
[Nora lifts her head up]
Judy whacking a giant mosquito with a tennis racket, causing the others to flee.
For a kid that was afraid of just talking, Peter goes through leaps and bounds of bravery, hanging upside down from a branch to get the game, creating a makeshift rocket launcher, and fighting off spiders with an axe.
Not to mention his confrontations with Van Pelt. He yanked the game out of this dangerous man's hands (knowing that this man has a gun), bites him on the leg when he grabs Sarah, and uses the aforementioned rocket launcher on him while his sister and Sarah pass the game to each other.
The stampede of animals, as they ran through the bookshelves and through the hallway. Again, as they run through the streets.
Alan bravely wrestling against a crocodile which was about to make a meal of Sarah when the house gets flooded.
When Van Pelt fires at Alan, Sarah attempts a Heroic Sacrifice by leaping in the way. She had no way of knowing there was going to be a Reset Button, and if there hadn't been, but Alan hadn't rolled the right number to reach Jumanji, her turn would have been next. Even if the game skipped her (and Judy), she had no way of knowing if Alan and Peter still playing would have ended everything and brought them back to life, but she still did it anyway. Aside from showing she loved Alan, that's pretty awesome coming from someone who was so traumatized she had to spend two thousand hours in therapy for 26 years—and it's also her making up for having fled and left Alan in the jungle all that time.
A moment that is as much "Whoa!" and a bit mind-blowing as well as awesome: when Van Pelt fires, Sarah leaps in the way, and the bullet is halted in mid-air... only to slowly be sucked back into the game. As it goes, Van Pelt's gun and then Van Pelt himself begin to follow it...and you realize that everything the game released is about to be sucked back into the game too. The payoff was about as good as the anticipation.
Just the entireReset Button scene is awesome, given how you've seen Alan and the others go through so much fucking hell and to see all of the mess the game has made get sucked back into Jumanji where it belongs is amazing, especially Van Pelt's own freak out as he's dragged back into the game.
In a more Meta awesome moment for the filmmakers, when Alan finds the buried game at the construction site, he lifts it out of the sand-filled chest it was hidden in, leading to a particularly cool looking shot of all the sand slowly sliding off to reveal the ominous Jumanji box, almost looking like it dissolves into the logo.
Peter takes the courage to ask Maria out. She accepts.
A point to Maria for telling off Rock that she's not his girlfriend and he is a loser.
Anytime Peter outwits Rock.
The Manjis getting revenge on the villains and saving Judy and Peter.
This moment deserves a better explanation: You have Ibsen, Van Pelt, and Slick trying to kill Judy and Peter, tearing up the jungle in nightmarish war machines. They finally corner them and it looks like the end for Judy and Peter, when suddenly Tribal Bob (who'd been forced by the trio to lie to Peter about there being no cure to Alan's centipede bite) appears with the other Manjis... and then a flash of lightning lights up the background, showing AN ENTIRE ARMY OF MANJIS. Who then proceed to charge and take out the villains in a rabid Curb-Stomp Battle, rescuing Peter and Judy.
Alan may had just recovered from that centipede's poison but that didn't stop him from gaining enough strength to get up and tackle the Stalker who was about to kill Peter.
Judy's science professor know his students well, even figuring out that Judy's lab partners dumped all that project work onto Judy. He lets Judy to get some rest while he gets her partners to explain the work they did.
After escaping Van Pelt and losing that thief, the heroes look into the box they stole and found a Juroceros horn. Van Pelt arrives and gloats about hunting the last of its kind and took the horn as a trophy. Before he could shoot them, the Juroceros arrive and Van Pelt has an Oh, Crap!. Cue a massive beatdown that even Alan and the others thinks its too gruesome.
Also, Alan, Judy and Peter watched in satisfaction at seeing the Juroceros chasing the thief.