That is actually an interesting point. I actually agree the physics could be crisper, but I tried to orient it at retro games and e.g. the original Super Mario Bros. 1 is much more slippery. I tried to go for a feel comparable to Super Mario Bros. 3 and Super Mario World, but maybe I should rather have gone with much higher ground friction, like e.g. in Commander Keen 4 or Super Mario Maker.
Having said that, I have tried playing the game with somewhat different adjustments there, and even making ground friction and acceleration really high - essentially removing all the “ice” effect - does not make it much easier, no matter whether on desktop with keyboard or on mobile with touchscreen.