Spoilers ahead, obviously

I don't know who actually plays this game anymore, or if this will even help anyone, but I hope it can save you the hour of googling and deep, hard thonking it cost me a few days ago.

The run itself is quite simple; you start with the Silver Mail, Beast Killer, Time Helmet to run further, whatever shield you feel like and any fast boots that aren't Duel Greaves, as you will be running from some unnecessary fights if you have to.

The Silver Mail and Beast Killer are used to skip two mini boss fights, granting you high levels and the Brave Sword respectively. You begin the run as usual, dashing to the first village. Ally with the nun, as she'll save you if you accidentally run to 1 hp before a village, so you can dash out of a fight with the heals that she provides. After this, dash to the bridge on the right, and move directly north from the bridge to the cave entrance.

Use this path, and travel directly downwards until you see the mini boss guarding the stairs to the final boss. Enter this fight, and immediately leave, to gain the healing from the nun. Immediately go back into the fight, dashing through the mini boss, killing it instantly before its attack can spawn. Go down to the village, recruit the bard if you feel like it (it doesn't really matter) and heal. After this, go up the stairs you just unlocked, head west, then north, to the ladder in the ground. Enter the cave, killing the mini boss with a dash to instantly remove it from the planet, gaining the Brave sword.

Finally, return to the village where the Bard was either recruited or left to rot, healing one last time, before killing the mini boss underneath the village (Optional, not too sure if it's necessary but I did it with enough time to spare. Dash the whole fight.)

Heal again if needed, and wait outside of the final boss's castle until 5 seconds are left on the clock. For whatever reason, the boss has massively reduced stats (Apparently equal to the PSP version's final boss) if you start the final boss from 4.99 seconds downwards. You have plenty of time to dash through the final boss, killing it before 30 seconds have passed, likely earning you the achievement, "A Real Hero and a Real Human Being".

Best of luck, lads.