The premise of the deck is very simple: remove my opponent's threats until I am able to land and protect my own.
The combination of removal and counterspells give the deck flexibility in what it can hit. Harnessed Lightning hitting early drops with low-medium toughness gives a decent start, with the upside of usually leaving enery left over for the Dynavolt Tower. The Tower itself pulls double duty as a far-reaching removal tool or as a win condition if not dealt with. Skywhaler's Shot allows the deck to hit high-power creatures with ease, especially ones that Harnessed Lightning struggles to remove such as Awoken Horror, Avacyn, and Heart of Kiran.
The host of counterspells remove particularly difficult threats before they ever hit the board, while powering the Tower if its on the field. These are usually saved for threats like Gideon, Heart of Kiran, Bristling Hydra, or Electrostatic Pummeler. Spell Queller also has the advantage of stopping these threats while pressuring the opponent, making it a valuable tool.
Torrential Gearhulk is the main win condition, presenting a threatening body with a powerful etb effect. The effect means I gain value from the Gearhulk, usually in the form of removal or draw power if it gets removed. Flash makes it a versatile piece, either flashing in during combat to take out two creatures at once, or at the end of the opponent's turn, granting pseudo-haste.
The other win conditions are Dynavolt Tower and Wandering Fumarole, though Fumarole is typically a last resort while Tower is plan B.