This was a very fun and very unexpected concept that I spent a lot more time in than I probably should've and I will definitely be gunning for that high score if I can figure out the secret. (Seriously 199, how). Other than that though it definitely and some interesting strategy with the fact that the boulders move on their own timers and don't move when you're not moving.
Combine that with their "healing", and you've got an interesting combo for a last second "Oh god that die is gonna kill me" moment. Like the rolling 12s. Those were not something I was expecting at all. But they definitely fit, and the healing mechanic makes sense etc.
I will say having your die take damage could be interesting, though the difficult is pretty good at the moment so I'm not sure what it would end up adding? Other than probably removing what is an interesting strategy of essentially blocking them yourself at the moment. So might not be worth messing with.
One final thing (sort of) I will say though is that it was a little vague as to how much health the wall had. It took me a few times accidentally letting stuff through to figure out that it was a 3 health per piece situation. Which was good to know.
Also (actual final thing) some sort of, buff dice could be interesting for keeping it going high score wise. Something with speed, or double movement. or healing etc.