Shadow of the Colossus remake uses 'original game code

This was confirmed by Bluepoint Games.

Nomad's blog: Unused/Beta Colossi

Shadow of the Colossus remake gets comparison video and Special Edition – Destructoid

A stunning new take on 'Shadow of the Colossus' - The Washington Post

SHADOW OF THE COLOSSUS on PS4 system introduces the awe of its unforgettable world and towering creatures to a new generation of gamers, while

Shadow of the Colossus - PlayStation 4

Shadow of the Colossus Remake PS4 vs HD PS3 (First 15 Minutes) : r/Games

Shadow of the Colossus Version Differences - Shadow of the Colossus and ICO Guide - IGN

Review: 'Shadow of the Colossus' has resolution to dig into details – The Mercury News

Review: 'Shadow of the Colossus' is one of the best game remakes yet

Unused Colossi, Team Ico Wiki

Shadow Of The Colossus Remake Vs Original, remake, Shadow of the Colossus, How do you think the Shadow of the Colossus remake compares to the original?, By Who Remembers?

Shadow of the Colossus (PS4) REVIEW - A Gigantic Success - Cultured Vultures