Rick Lane: Underworld Ascendant Review. It's a mess. In: PC Gamer. Future US Inc., 21. November 2018, abgerufen am 16. April 2019 (englisch): „Underworld Ascendant is phenomenally bad, a catastrophic mess of poor design ideas, woeful execution, and bugs the size of buildings.“
Andy Chalk: Underworld Ascendant developer video promises that fixes are coming. In: PC Gamer. Future US Inc., 20. November 2018, abgerufen am 16. April 2019 (englisch): „It's not unusual for a crowdfunded indie game to have issues, especially one as ambitious as Underworld Ascendant, but even in that context, that's a lot of ground to cover.“
TTLG. 9. März 2001, archiviert vom Original am 9. März 2001; abgerufen am 20. Juni 2016.
The Team at OtherSide: Stygian Sentinel, Issue 30. Halloween Edition. OtherSide Entertainment, 31. Oktober 2016, archiviert vom Original (nicht mehr online verfügbar) am 5. Januar 2017; abgerufen am 4. Januar 2017 (englisch): „A Special Word from OtherSide's Paul Neurath – It probably comes as no surprise, but it's taking longer than we'd hoped for Underworld Ascendant to come together. The release will extend beyond the original November 2016 date. … Before we will be ready to share an updated release date, we want to get over the hump on the key innovations and know that they are working smoothly. In February, we expect to share a new Prototype build with Backers that shows much progress.“
TTLG. 9. März 2001, archiviert vom Original am 9. März 2001; abgerufen am 20. Juni 2016.
The Team at OtherSide: Stygian Sentinel, Issue 30. Halloween Edition. OtherSide Entertainment, 31. Oktober 2016, archiviert vom Original (nicht mehr online verfügbar) am 5. Januar 2017; abgerufen am 4. Januar 2017 (englisch): „A Special Word from OtherSide's Paul Neurath – It probably comes as no surprise, but it's taking longer than we'd hoped for Underworld Ascendant to come together. The release will extend beyond the original November 2016 date. … Before we will be ready to share an updated release date, we want to get over the hump on the key innovations and know that they are working smoothly. In February, we expect to share a new Prototype build with Backers that shows much progress.“
Underworld Ascendant: Explore the Stygian Abyss, at your peril. (Memento vom 6. September 2015 im Internet Archive) (englisch); abgerufen am 2. Mai 2016. Zitat: „In Underworld Ascendant, you return to the Abyss as the Avatar generations after the events of Cabirus' failed colony.“