Are they the same as the original? I heard some say it is different and changed similar to how doom 3 was. anyone know for sure?

The Redux versions are on refined engines used in Last Light (e.g. it looks nicer, runs better) and the stealth system from 2033 is redone. To make a point to compare to, it's like Doom 3 Vs Doom 3 BFG Edtion

Last Light is basically the same. They fucked up 2033 though.

It is generally agreed that the first game (2033) is better in the original than the Redux. Same as Doom 3 vs BFG edition if you ask me.

When starting a new game in 2033 it asks if you want the classic (hard) balancing or the reworked one. But I don't know if there differences in gameplay between original and classic mode in Redux.

I bought Metro 2033 long ago on dvd and activated it on Steam (as I had to) and it recently effed up and started looking like the redux version in the middle of the game.

Redux has classic mode? Must have forgotten...
Anyway, there are a ton more differences between the 2. Character designs, voice overs, some changes in some levels here and there, gun mods etc. Even minor things: for example, in the original, there was shattered glass on the floor in places which when stepped on, made nearby enemies aware of your presence. That is completely missing in Redux. I also read that they fucked up the enemy AI in Redux.

I just recently finished the non-Redux 2033 (it was for free on Steam recently), and it did somehow feel better. More "raw" and gritty. The Redux engine seemed way too polished for a game of this type. Not nearly as atmospheric.

Balancing. More ammo in the new mode etc. Way more changes than just those modes though.

The original game is better? Yeah, is it hell. The redux is a fine improvement. It fixes a lot of bad elements the original had. Better stealth etc.

If you call being in shadows = perfectly invisible better sure.

I didn't know you could still get the original.

I recently played through Redux (after playing the original version several years ago), didn't really notice too many gameplay differences while playing Ranger/Survival mode. Stealth really did get a bit easier though.

People keep bringing up that a few textures and the smoke effects in the original looked better - which is true, but the overall lighting in Redux is way better, character and enemy models are immensely improved and the frame rate more than doubled for me in the more critical locations. Also, it doesn't crash.
Id definitely recommend the Redux version.