Is there a game in-between? I just finished Return to wolfenstein and am now trying to get into Deus ex but I just can't get the feel for it. Can anyone make a recommendation to make this transition easier? Thanks!

Maybe BioShock (though it doesn't have an inventory it does have money collecting and character improving through plasmids) or something like Elder's Scrolls Oblivion/Skyrim (is open world instead of "open mission map" but hey :D). Coming from an FPS like Wolfenstein I would go with BioShock though.

Just remember, Deus Ex plays in first person, but is not and FPS (in fact, you have a stormtrooper's aim until you improve that... I hated that since I'm actually aiming).

Maybe System Shock 2 ?

Yeah, I second this. Similar era. Sci-fi FPS/RPG but without all the text and dialogue of Deus Ex.

Cool! Thanks for the response guys. Im going to check out system shock 2 as its on gog.

Is it the gameplay you can't get the feel for, or is it maybe the futuristic setting? If it is the setting, I think System Shock is not the best game for an easy transition.

You should try Sacrifice .

You can also try Blood II.

Strife

maybe Thief 2?

if system shock is a bit much still, I would definitely recommend Bioshock. In my opinion System Shock 2 is a great game but Bioshock refined it to perfection. In my opinion.

Jedi Outcast or Jedi Academy

You can't go wrong with these games that is for sure.

A Return to Castle Wolfenstein and Deus Ex mash up should be made and it should be named "Return to Ex".

Sometimes treasures get lost between times.
Some of classic games couldn't brought back because devs lost their source code.