Needed a moment to understand whatI was supposed to be doing.
Considering how there isn't much to the first three levels, I think the washing machine should have much less HP. Like, 3 goops to get through LV1 to understand what your goops are doing, and what payoff there is to hitting them. I was honestly ready for the game to end after the first bar because it just took that long without any challenge. Having to stand still to regen your goop is interesting, but only later when the WM's attack has a non-zero chance to hit. And even when you do get hit it doesn't feel like you'll ever die, so it's affordable to just regen your goop while tanking it because it doesn't matter.
Maybe the water the WM spills could fill it up, decreasing how much room you have to run, and thus putting a timer on your battle. It's a good game visually, but lacking in challenge and reward for the effort of having to hit this thing 100 times.