This is a super fun game.
To me, the best play was to start safe (building stairs, getting back to the base) until I got to the yellow coins. Then, I would always go as deep as possible and get as much resources as I could and die, respawn with half resources, buy whatever I can and keep doing that until my battery was enough to get the drill machine. Then I got to the end of the game and killed the boss!
I don't have much feedback to give other than maybe a better visual feedback when you hit enemies, but to be honest I'd always avoid them because it wasn't worth to kill them anyway (AFAIK). The drilling experience was super fun, and it's nice that we have to be clever about our digging in order to prevent getting trapped. The powerups make sense, and the music is an absolute blast. This is a really solid entry, great job!