(preferably at 40fps locked)
- Gothic 1 & 2 and Elex 1 
- Msg V 
- Been playing a lot of AC: Black Flag on the deck. Also Windwaker HD and Outer Worlds. Dunno if you’d count the last one as open world, it’s hub-based with an open world feel. 
- How has no one Horizon Zero Dawn yet that game is great on deck - I came looking for this. It runs well? Been in my backlog for ages. Seems like good steam deck material. - see my response to the other reply 
 
 
- 7 days to Die 
- Minecraft! 
- GTA IV. 
- Some open world that I’ve played on the steam deck that run well with or without slight tweaks: - RDR2
- Witcher 3
- Spiderman
- Cyberpunk 2077
- GTV 4 & 5 (+ trilogy)
- Arkham City & Knight
- Hitman : World of Assasination (not really open world but still plays well with huge environments to explore.)
- TES Series (mainly Skyrim, I haven’t tried the rest but haven’t seen them run well)
- Mad Max
- Metro Exodus (and series but they’re not exactly open world)
- Project Zomboid
- Days Gone
- Fallout 4
- Zelda : BOTW
- Super Mario : Odyssey
 - And the list goes on, but I enjoyed the switch titles along with GTA, RDR2, Hitman & Spiderman the most. 
- No man’s sky! 60-50 FPS. Can drop at 30 ish when it loads some new stuff on the map but most of the time 60 fps lock! 
- TES Oblivion 
- Yakuza 0 
- Tears of the kingdom… 💯 
- Just Cause 3, GTA V, Dragons Dogma, Just Cause 4, Just Cause 2, GTA IV… should I continue? 
- Witcher 3 
- Oddly enough, Dead Rising 3. This required some insane power back in the day to run but the Deck runs it like a champ. - It does drain the battery though, but boy is it fun. 
