Spider-Bite

With this deck, in addition to Gwen's hero set, you have ten additional response/interrupt events you can use to trigger Gwen's ability. Four of those can be used during the villain's phase. Your only non response/interrupt events can be used to trigger those if Gwen starts her turn exhausted. Toe to Toe isn't one that immediately came to mind for her to use, as she's an average 10 health hero, but she does have a three defense. By using it, she does five damage, can mitigate much of it defending, or trigger You'll Pay for That! to ready herself.

She will be a strong attacker, potentially getting fourteen damage in one basic attack (2 Base + 1 Combat Training + 2 Godslayer + 3 Mean Swing + 3x2 Skilled Strike). Bug helps enhance this by being able to do four damage with ranged and piercing. But that's not all she can do.  You'll Pay For That! and Chase Them Down combine with her Phantom Flip to give decent threat removal.

If you want to go over four cards, Moment of Triumph could work as a decent heal if you're phase lower health minions. Boot Camp might be worth playing to get Bug up to five attack.