This patch removes the 8 frame delay after changing directions and reduces it to 1 frame. You can still change direction without moving by a quick tap of the direction pad.
The patch only modifies one hex value in the rom. It is a massive improvement over the original game.
You will need an IPS patch installer to patch the rom such as Lunar IPS http://www.romhacking.net/utilities/240/
Note: This rom can also be patched with the music fix hack without issue.
No-Intro Name: StarTropics (USA)
(No-Intro version 20130731-235630)
File SHA-1: FDD3D68C7B5B2F9DC7EC50D9888B0A8EDBAAEC28
ROM SHA-1: 74C53FE9AC779F146C59AC01E701C9BF912B3C7B