Groot Beats all GMW in Expert! (only cards from waves 1-3)

Beats all the scenarios in Galaxy's Most Wanted in Expert. Yes, including Ronan.

First, you need to mulligan hard for "Fertile Ground". That card is the most important.

Rely on confusing the enemy as much as possible to be able to flip back to alter-ego and build-up on growth tokens.

The second most important card is "We are Groot". Giving tough to allies is extremely good. Do it often.

To win, rely on "I.AM.GROOT." for 10 damage, but for final pushes also use vine spikes.

The two odd-ball cards here are "Target Acquired" and "Spycraft". They are there for preventing Nebula and Ronan to get stalwart. Nebula gets it via techniques, and Ronan via the universal weapon. The idea is to set these preparations up and use them to cancel either the boost card or revealed encounter card that would attach to them.

If not playing against Nebula or Ronan, just remove "Target Acquired" (the deck has 41 cards, so you can remove one).

The other tip is to prioritize playing Sonic Rifles. They are expensive but allow for a lot flexibility to flip to alter ego a couple times, which is the core strategy for Groot.