I think the base scene has a nice cute vector vibe, but the biggest issue is readability. The insects are the main gameplay objects, yet they blend into the grass and background a bit too much.
I’d make the background softer/more muted and push the insects forward with stronger outlines, brighter colors, slightly bigger sprites, or small shadows/glow. Right now the background, decorations, and insects all have similar visual importance.
Also, the insects and the environment could be a bit more stylistically unified. Either make the insects more simple/cute like the landscape, or add a bit more detail/texture to the environment.
Overall, I don’t think it needs a full redesign. Better contrast, clearer silhouettes, and stronger visual hierarchy would already improve it a lot.