A fast flying to top room before killing the bat after running in the cave saves 165 frames. Thanks to pokefantom.
9 seconds has been saved due to japanese version. 3 hits is enough to kill the very first dragon (Link to video)
I won't submit it.I may do in the futur (if some improvments found and if I'm sure about publishing it). Used emu: snes9x 1.51 Encode: (Link to video)