The creatures in this deck are fairly standard for the Mono-Red deck. See below for explanations.
Ahn-Crop Crasher is a nice, beefy 3/2 body with haste for . The ability can be quite relevant, and it's just a good card for the 3 mana slot in this deck curve.
Bomat Courier is a 1/1 with haste for , which is nice, I guess. It's weak stats are a bit off-putting, BUT the ability is what makes this card so good. If played turn 1 (maybe turn 2...) those cards start to add up and become a very nice way to replenish the hand during the midgame. There are advantages (extra cards, of course) and disadvantages (Hazoret the Fervent wants an empty hand to attack/block), but I have found the disadvantages to be outweighed rather easily.
Dire Fleet Daredevil is just a fantastic card. Using an opponent's removal is amazing. Nothing better than hitting Vraska's Contempt with this card!
Earthshaker Khenradoesn't seem all that special as a 2/1 for , even with the haste. It's the eternalize that makes it sooooo good. It's costly to be certain (), but a 4/4 with haste that can render most blockers null and void? That's pretty solid.
Fanatical Firebrand is just good. Haste makes it really good, particularly first turn. Coupled with Goblin Chainwhirler, it is even better-- able to get in that extra point of damage to finish off a 2/2 after Goblin Chainwhirler enters the battlefield.
Goblin Chainwhirler fits nicely into a mono-red deck. The costs aren't too high and it just works well. A 3/3 body with good ETB effects-- can't complain.
Hazoret the Fervent has haste and is indestructible. Moreover, the card can ping my opponent for two life. Best card in the deck.
Kari Zev, Skyship Raider is okay, but it has menace (and first strike) and, more importantly, brings in a 2/1 attacker each turn I attack. That's one additional creature that needs to be blocked. Solid card.
Rekindling Phoenix has, in most red decks, replaced Chandra, Torch of Defiance. I'm not agreeing with that. It's a fantastic card (I only own a single copy, unfortunately), but Chandra, Torch of Defiance is stronger.