Most Kerrigan builds rely on the combination of Primal Grasp and Impaling Blades to deal damage, which has a number of drawbacks:

• If you whiff the combo, you're pretty much dead weight during a fight
• You need to save your abilities for damage during fights, which prevents you from using them to lane, pressure, or take map objectives
• Several talents, such as Sweeping Grasp become mandatory in order to allow you to execute the combo
• This build eats mana

I found this build frustrating, so I began to experiment with others. Eventually, I settled on this one, which has several advantages over the typical Kerrigan build:

• Your damage output is decoupled from Primal Grasp and Impaling Blades, allowing you to use these abilities for control (rather than your primary source of damage output)
• Your autoattacks deal splash damage, allowing you to lane and take objectives much more effectively than Kerrigan usually can; this, in turn, gives you more stacks of Seasoned Marksman, which improves your damage. In addition, dealing splash damage allows you to acquire shields through Assimilation much faster than usual, making you less fragile.
• Your damage output scales passively over time with Seasoned Marksman, which benefits Fury of the Swarm and can be further amplified by Searing Attacks and Nexus Blades
• As a melee assassin, you often need to hang on the fringes of a fight, waiting for the opportune moment. With this build, each hero your team kills while you're waiting gives you 1/3 of a stack of Seasoned Marksman, allowing you to grow in power while you wait.

Some disadvantages:

• This build is less surgical, precise, and inescapable than the typical combo build
• The player must still balance mana expenditures to have enough mana for Searing Attacks. Though Searing Attacks does not consume mana if you do not attack while it is active, it also has a longer cooldown than your other offensive abilities
• This build starts slowly: until your team hits level four, you will have difficulty laning, and until your team hits level seven, you will have difficulty taking down enemy heroes.
• This build has fewer "fire-and-forget" qualities than the typical combo build: in order to do damage with Searing Attacks, you need to remain in melee range for five seconds.

• Tier 1: Seasoned Marksman
• Tier 2: Fury of the Swarm
• Tier 3: Searing Attacks
• Tier 4: Summon Ultralisk or Maelstrom, depending on team composition and player preference. I like Summon Ultralisk, for several reasons:
  • It places an additional threat on the field (something else for the enemy team to shoot at)
  • It allows me to multitask by assigning the Ultralisk to attack a tower, a hero, a gate, an objective, etc.
  • It has a shorter cooldown than Maelstrom and can therefore be justifiably used on map objectives or structures
• Tier 5: Sprint
• Tier 6: Blood for Blood; Aggressive Defense is theoretically possible with this build for increased sustain, but in practice, the immediate healing and offensive power provided by Blood for Blood is usually more valuable.
• Tier 7: Bolt of the Storm or Nexus Blades; this choice is dependent on team composition

• Level 1-4: Lane from behind your creeps to build XP and Seasoned Marksman stacks; engage heroes only when you have an overwhelming advantage
• Level 4-7: With Fury of the Swarm, you can engage creep waves and map objectives (such as the undead in Haunted Mines or the skeletons in Blackheart's Bay) with impunity. You can gain stacks of Seasoned Marksman much more quickly now, but you are still vulnerable against enemy heroes; engage cautiously.
• Level 7-10: You should now have a fair number of stacks of Seasoned Marksman; combined with Searing Attacks, you can now cut down enemy heroes more efficiently.
• Level 10-13: Summon Ultralisk is not a game-changer, so deploy it with impunity. Use it to scare off ranged assassins or soak damage from them; also use it in team fights or to engage mercenaries or enemy structures. Concentrate on favorable engagements and staying alive until you reach level 13
• Level 13-17: Sprint, on the other hand, is a game-changer. You can now pursue heroes more effectively or escape situations in which you might have otherwise died. Take advantage of this flexibility; be bold.
• Level 17-20: Choose Blood for Blood: it can heal you in a pinch and is better against Warrior heroes, since it steals a percentage of their maximum health. Blood for Blood is also better for chasing slippery heroes.
• Level 20+: Choose Bolt of the Storm if you need the mobility (either to chase or to escape); choose Nexus Blades if you have strong support and if you want to boost your DPS and your sustain via Assimilation