I think the boulder should shrink a little every weight reduction upgrade. I also think there should be some way to see you stats (strength level, top speed, the amount the weather hinders you, [it'd be called "weather reduction"] and possibly unlockable upgrades? {one example would be at like 100m or something an upgrade called "sugar" appears to buy and it gives you bursts of speed at random intervals})
The boulder shrinking is on my todo list and will be put out in a future update.
The stats you’re referring to exist, however I’m only enabling them for debugging purposes. I will consider enabling them for regular gameplay.
Also I will be working on making as many new upgrades as I can for when the final game is released on Saturday.
Thanks a lot for the feedback!