There's still plenty of treasure hunting and classic TR navigation puzzles, although as the trailers imply it's very plot driven and sometimes feels more like you're watching a movie than really have control of the character. That said it's an open world with plenty of things to collect and upgrade your character and weapons, so that can be pretty addictive. I just played 10 hours straight and finding it hard to stop, and the last game I did that was Horizon Zero Dawn. So yah this is pretty darn good, and the graphics are great. I just watched the associated 2018 movie and this game is far better than the movie.
Just getting into it, has all the things I used to love about customizing the mechs and the gameplay, but also features a massive universe with freedom to roam, and lots of opportunity to grow. For example the first few missions you can't salvage any mechs, but as you gain experience and salvage credits you can salvage a lot more, which will include mechs, weapons, and ammo. There are also mech repair bays which reduce the need for costly repairs after the mission. Lots of customization options, and in the tradition of past Mercenaries titles there isn't much of a storyline so you are free to do what you like. On the other hand it's not clear there is any way to "win" the game, so I'm not sure what my goals are here. Just have fun destroying and getting better mechs and weapons, I guess? The user interface is a bit awkward, there is a learning curve and some unintuitive things, like I'm still not quite sure how to sign up for and start a mission. Seems like that shouldn't be hard to figure out.