But big monsters always give gems, so it kinda raises your score that way.
this guy makes a good point, for 1 bomb you can kill a giant spider, and get sticky paste (worth 3000+ gold) and 2/3 gems which tend to be pretty random, which is a few thousand gold as well, all for a single well placed bomb.
considering 3 bombs only cost 2750 to begin with, it puts you up either way.
the entire game revolves a lot around luck, not only the gold mechanic. obviously you need lots of good spawns or to use the ghost tactically (with a jetpack for example, he is easy to dodge, i once got verrry lucky on my best run yet, a boulder from the golden idol destroyed the top layer of one of those dudes that hide in the walls with 2 treasure chests, the boulder didnt destroy the chests, i made the ghost go through all of the gems to turn them all into diamond, instantly i get like 60-70,000 for those 2 treasure chests, ended up my run with like 470k no city of gold).
and getting a perfect speed run will also require a bit of luck, sometimes you can get terrible layouts, or simply go the wrong way, and have to waste bombs just to save time, or get dark levels which are obviously much harder to speed run.
high score is fine, high score is just score, and score is gold, as well as time to beat game.
i see no changes needed.