Chewbacca Defence: He will often attribute things going wrong or unexpectedly to "science".
Cliffhanger: In his blind LPs of well-known games such as Final Fantasy VI, he coins the idea of a 'reverse cliffhanger' - when the audience mostly know what's going to happen next, but Jake himself doesn't.
Cool Sword: Owns one, as shown in one of JoshJepson 's vlogs. They use it to cut fruit. And then try to kill each other. Obviously.
Establishing Character Moment: An aversion; many viewers' first exposure to him was through the Battletoads race, in which the usually very even-tempered Jake is constantly raging and swearing at the game.
Forgot About His Powers: In his P3 FES Let's Play, he complains that one of the Guardian bosses in Tartarus would be so much easier if he had access to a party healing spell. Several parts earlier he showed off Cadenza, a fusion spell that heals the whole party. Not once in his many attempts to defeat the boss does he remember this, which is most likely understandable considering the requirements may be more trouble than it's worth.
The Battletoads race may have brought the worst out of him.
Heroic RROD: In the sequence of events immediately following his below-mentioned Large Ham moment, his voice is pretty hoarse, something that he himself comments about.
Hilarity Ensues: Jake wanted a zombie-themed game to LP alongside Persona 3, so he went and picked up the only one that looked interesting to him for a blind LP. He picked Lollipop Chainsaw. His reaction to the intro video alone is enough to let everyone involved know what they're in for:
Old Shame: He considers the Battletoads race to be this. When it was brought up when he was guest-staring on one of P Cull 44444's streams, Jake admitted that he's completely disgusted with how much he raged on camera.
"So, you know who we haven't hung out with in a while. That would be... Kanji. (beat) But we're still not gonna hang out with Kanji. The comments section just exploded. Oh my god. Heheheheh."
Verbal Tic: "Gladly", "Truly", "Nice!", "Sad.", etc.
He also says 'however' a lot to fill gaps between sentences.
Weapon of Choice: In his co-op Resident Evil 5 LP on Proton Jon's channel, Jake enjoys using the stun baton and will attempt to use it on an enemy at least once per part. Leads to Irony when he starts frequently encountering enemies who also have a stun baton and manage to get him with it.
SuperJeenius: Did he say 'insects'? Cuz I really hate bugs...
More specifically he really doesn't like spiders, which comes up in his Resident Evil 5 co-op with ProtonJon.
It's practically becoming a running gag in the RE 5 LP that whenever Jon starts to give warning about a new enemy type being introduced ("One of your favorite enemies from Resident Evil 4," "A traditional Resident Evil enemy," etc.), Jake pretty much always thinks it's spiders, even after they've already encountered them.