Murder on Eridanos is the second DLC for Obsidian's The Outer Worlds. I've played a lot of Obsidian games, as well as several by Black Isle (their spiritual predecessor) and loved most of them.
If you like The Outer Worlds at all, you'll like this too. It preserves the cartoon style of the artwork, adds a few new beasts and villains, and generally carries on in the same vein as the base game and the first DLC, Peril on Gorgon.
The setting, an archipelago of jet-engine-supported floating islands, is quite lovely to behold.
There are upgrades to various weapons, with things that previously had Mark II versions now being available as Mark III, and Ultra versions of other weapons now available in Hyper versions (or is it the other way round? Is Hyper superior to Ultra or is it vice versa?).
Where Murder on Eridanos separates itself from the rest of the game is in its pacing and plot. It's a murder mystery with a twist in the tail. There's not nearly as much combat as in the previous two episodes and a bit less "Fedex", though that's not entirely eliminated.
Good bad jokes and cultural references abound. The boss fights are less hard than in the first two episodes. They recommend you are at least level 30 to play this, and probably don't let you start it before you reach that level, but it's far easier than Peril on Gorgon.
The point of this episode is the story, not the combat, of which there is really very little. It doesn't leave a lot of room for multiple replays; once you figure out the murder plot, you've had most of your fun, and some will figure it out pretty quickly, but it's nicely done.
They did fix a couple of annoyances; if you only have saves from too late in the game to backtrack (which killed Peril on Gorgon for some) you are now given the opportunity to backtrack and play both Peril on Gorgon and Murder on Eridanos from a point before the endgame on Tartarus, which you can then do for a finale, if you wish. Second, they fixed the achievements thing for players on a PC; if you play from a save where you did all the things in Peril on Gorgon that should have got you Steam achievements, you'll have them awarded retroactively when you first play from that save after installing Murder on Eridanos, and you'll get the achievements from Murder on Eridanos as you earn them.
It might not be worth the stand-alone price, but if you bought the expansion pass originally, it's not a bad deal.
On a scale of -3 to +3, I'd give it a solid 1 (that's about 71%, if you slept through arithmetic).