Vox Machinae

Vox Machinae has been hanging around in Early Access since 2018, but its full-featured release arrived this past May and it’s an excellent mech sim for the Steam Deck. To be fair, some animations are wonkier than I’d like them to be, but Vox Machinae strikes a nice balance between simulating the experience of driving a massive machine and making the process easy enough to catch on to that you don’t need a degree in rocket science to do the most basic of movement tasks.
The game has you reading out actual meters and features in a simulated cockpit rather than a HUD, and I think this aspect translates really well to the Deck. Having to look down at your throttle to check your speed, or call up an actual second screen to zoom in on targets, really sells the experience of being inside a mech and on the Deck, the use of the expanded controls makes you feel like you’re piloting a complex piece of machinery.
The left touchpad, for example, allows you to quickly boost with your jump jets and move in the direction your thumb is pointing. When you do, your avatar actually moves their hand to a different joystick to perform this operation, so there’s this really cool parity between what you’re doing on the physical controls of the Steam Deck and what your character is doing in game. It’s a perfect example of how the Steam Deck’s expanded control features can open up new and unique gaming possibilities.