I am experiencing heavy lag in *some* rooms. I am nearly certain that it is due to the dynamic background: the larger is the portion of the background currently displayed, the heavier the lag is.
In the picture I uploaded I circled in red what I mean with dynamic background: it takes me around 6 seconds to walk from one blue point to the other. In the exact same room, just a bit further down, where there is no visible dynamic background, the game runs perfectly smooth.
I am playing on a gaming laptop with a dedicated graphics card, which isn't turned on by AdventurOS.