Protecting with allll the upgrades!

This is the epitome of a slow-burning, build-out deck. Meaning, your battles will be long, but fortuitous.

Hulkling's most valuable asset is his versatility to switch his focus between thwarting, damage and defending. Early game you will want to focus on survivability as you add upgrades into play. Adding Armored Shape is recommended for both defense and healing. However, if your villain starts with a side scheme then Winged Shape, to remove threat as you're defending, would be fine as well. In addition, I would mulligan for Symbiote Suit. Hulkling benefits tremendously from the extra hand size, basic power upgrades and health. The extra encounter card dealt while having Symbiote Suit attached, typically, is fine considering your added power and economy.

During the villain phase, where most of your work will be done, you will have multiple avenues to pursue. Main scheme gaining a bit too much threat? Play Not Today! as you're defending. Don't feel like taking damage later? Play Never Back Down, especially if you have Armored Vest, Defensive Conditioning or Symbiote Suit in play.

During the hero phase, focus on cleaning up any minions/side schemes in play with Shapeshifter Strike, any allies in play and your basic abilities after triggering Indomitable or adding a new Shapeshifter Upgrade into play. With any remaining cards/resources you should continue to build out your upgrades.

As you have gained/maintained control of the board and are moving towards focusing on attacking the villain you can convert to Hulk Shape, using events to trigger Hulk Shape's Hero Response to target the villain, your basic attack, allies (especially Iron Lad if your other allies are in play) First Hit and Shapeshifter Strike.