Hi guys !
Here's my video of my speedrun of Kamiko under 30 minutes,without dying and with all 4 secrets and all upgrades collected.I hope it helps !
I used Yamato,the 1st character.She's very OP and the game is very short and easy with her.You should unlock this achievement easily by using this character.
It's one of the best road to take,if you want to good timer at the end.But it's not that hard to beat the game under 30mins (i did it under 20).Use the dash a lot,it's very important for the speedrun !
Have fun ! :)