Mod Upfront: The game can be modded for 4k. MGROverride will change the meaning of 800x600 to be any resolution you patch it into. The downside of this is that some hud elements glitch and that you have to reset the resolution to 800x600 on start to re-apply it. Which is not perfect, but playable. There are a few other nice mods like to improve the camera or textures.
I played the game back when it came out and enjoyed it. Challenges can be trying at times, but that's what they are for.
It's a great game that can best be summarized as "designed for fun". The game follows the story in chapters. It has a lot of collectables and challenges in every chapter. However, you don't have to worry if you didn't score an S rank in a chapter or missed a collectable. You can just go back and replay it on the same save (Story -> Chapter). You are rewarded with a currency that you can exchange to improve your abilities, weapons and armor (-> Customize). That means you can just play the game, get better at it, improve your character and revisit missions for challenges.
The style of writing is intentionally cheesy and fun - set against the serious backdrop of war and cyber implants - just as you want your metal gear. Who doesn't love a German capitalistic mad scientist on his team eager to augment you.
I would have loved to see the game improved to support higher resolutions etc. out of the box. I very strongly doubt it will be patched in, but I am very happy to finally be able to replay it. Also, while I love the game, it's not perfect - esp. by today's standards. Criticism of it's camera (and even combat parry mechanic) is somewhat deserved. So historically, it's a 4. As-is it's a 3. Konami has long lost the status of caring about games. Given the IPs they own, hopefully one day they can revive their dead corpse and not just milk the back-catalog (esp. without improvements). But I take it.
Very happy about this drop. Please more (old/new) AA / AAA on GOG - I don't do steam :)