
You have to use Proton 8.0-5 and disable steam input in options, otherwise it won't detect a controller as being connected in the games options menu, which allows you to enable the controller in set options menu. After that it works perfectly.
when you first launch the game it'll get stuck in a loop on the main menu trying to load, just Force exit and restart and it'll work fine.
If you're looking for the DLC, the only place you can still buy it is in the Dead Rising 2 Complete Pack on Humble Bundle. If you purchase it and redeem all the keys the DLC will load like normal. they were delisted from Steam at one point because of an issue, but the issue apparently is no longer present, but the DLC is still delisted.
unfortunately, this complete pack is $32 and never goes on sale. figured I'd put it out there regardless.
This runs like a Dream on Deck, It's too bad it's got so many minor issues that can keep people away from it, I only found out that proton 8.0-5 thing on a random Reddit post After researching for an hour. If you look things up, you'll see a bunch of stuff about downloading Xbox 360 controller drivers or using a community made controller mapping, you don't need to do any of that. Just use proton 8.0-5 and enable the controller in the options menu.

Upon pressing START in the main menu, the game gets stuck on an endless "loading dlc" screen, whether you have dlc or not. Exiting the game through steam and restarting fixes this issue.
Refuses to launch when connected to the official Dock. Different proton versions did not help.
I did not encounter the controller issue cited by other users. Steam deck controls work fine.
Game will not, under any circumstances, detect the Steam Deck controller inputs. Tried various Proton versions. Nada.
Sandbox mode save file was randomly corrupted after progressing to a certain point in story mode. I was luckily able to go back to a previous save and it was fixed
The game would sometimes crash at random points without warning (maybe my steamdeck was overheating?)
Overall it ran a stable 60 frames the whole time and I definitely recommend on steamdeck
No tweaks needed, found the game worked perfectly and managed to complete it with no problems.
Played co-op with someone for a couple hours, no issues.
Just install and play

First time open the game got stuck in the screen Dowloanding content... just restart the game using the Steam overlay.
maped l3/roll to l4
See conclusion notes 4 hours and 15m
crackling when resuming from sleep. ot completely horrible through the speakers, but very noticeable
3 hours and 45- 4 hours and 15m. 95% battery Didnt spend a extensive time playing it yet, mostly focoused on visual and battery life balance. in game settings set screen resolution to 960*600 vsync off multisampling one blur effect off high zombie quality and meduim shadows texture filtering to 4x anristropic steam settings turn refresh rate to 50hz turn fsr on and set sharpness to 3. all text are fairly legible and looks good. their is supposed to be some bug that breaks it a bit. I'm unsure on the details
USE ALL SAVE SLOTS!!! Saves would revert to a bit ago
crashing a few times
For deck users First off this a horrible PC port, luckily deck gives you way less of a headache. Usually the game cant detect any controller other than a 360 and when it does you cannot switch between keyboard and mouse without reboot. Also some horrible performance on my pc but deck sees no problem on medium settings, no anti aliasing, and no multisampling. Now if you want to beat it you will problably end up getting in an infinite loading screen and need to change an ini file towards the end of the game. There are also some crashes throughout all versions, and ended up getting multiple save file problems. From my expirence i would say frequentally save in ALL 3 slots, and maybe stay away from sandbox mode as i found overwriting in past slots ended up losing hours of progress for me.