Section 8 and Section 8 Prejudice. https://en.wikipedia.org/wiki/Section_8_(video_game)
A fantastic pair of games which died too quickly because everyone saw the power armor and thought it was going to be a standard run and gun Halo style game. When in fact it had a mechanic that required dropping shields with certain types of weapons before you could then use other types to penetrate the armor. It also had a power management mechanic allowing you to move faster or use other abilities if you had the power remaining to do so.
As a result all the Halo/COD bro's bounced off the game because the few of us who took the time to understand and master those mechanics would just absolute wreck their faces. This unfortunately also included many critics/reviewers. Which results in a whole lot of "this game sucks". In this case the bliss of ignorance killed both games.
I enjoyed them immensely if briefly. They died too soon.
I forget which achievement it was but it was bugged keeping me from getting all of them. Curse you 1943! Still, an amazing re-visiting of the OG map/game. ❤️