Used a slightly different upgrade-focused route which loses some time getting money and upgrades, but makes up for it with faster Zone-4 and Zone-5 boss kills. Had a strange upper Lava Caves where the usual snake enemies didn’t spawn, but I won’t complain. Lost about 9 seconds to two falls in Zone-5, but otherwise a pretty clean run. Maybe it’s possible to get a one cycle Lava Worm kill with this route? If so, I think sub-16 might just barely be in reach.