He played Doom: The Dark Ages and realized melee doesn't feel as good in Mortal Sin as it does in The Dark Ages, so he went back and changed melee feedback to bring it more in line with The Dark Ages. It's definitely an improvement.
Metal Eden thoughts after playing a few levels: very fun run-n-gun cyberpunk shooter. The overall flow of levels is you have a bit of traversal while your Mission Control guy provides lore and context for why you're blasting your way through the city, broken up with combat rooms. You get a dash, jump, and rocket boost, which you can upgrade to hovering. You can recover ammo, armor and health using specific actions like ripping out enemy cores and then either consuming them or throwing them, but there's also static power-ups that respawn on a timer you can collect. Metal Eden also fixes my big gripe with Doom Eternal: you actually have enough ammo to have fun with your guns once you start getting upgrades for them.
Once you finish a city section, you take an elevator down to the planet's surface. There, you have traditional platform traversal alongside sections where you can turn into an armed and armored ball to cross long distances. Once you finish on the surface, your character dies, but it's okay because she's restored from a backup core back on the ship and sent to a different point in the city to accomplish the next objective.
I like the presentation. Corporate logos are everywhere, the palette is a mix of greys, whites, blacks, and reds. The most colorful thing are the enemies, which help them stand out more. Soundtrack is pumping techno/industrial like you'd expect, but it gets the job done. Voice acting is serviceable. Mission Control is probably the one part I do not like. I appreciate the background he's providing, but my God does he love the sound of his own voice.
Completing combat encounters also sometimes provides you with AMP cores that are used to upgrade your character. This can range from reduced cooldown on core-ripping and melee to adding new abilities like slow-mo. You also collect "Dust" by both killing foes and searching the stage, which is then used at P.I.G. stations to add secondary fire modes to your guns and upgrade them.
It is a UE5 game, so it makes my system run a bit hot even if I turn off the fancy upscaling and framegen shit. Even with those off it looks all right and runs smoothly enough on my rig that I don't feel like I need them.
It's $31.99 US right now, and it feels like one of those surprisingly fun budget games you'd pick up at the store on a whim. I can recommend it, though I'd wait on a sale if you're not sure.
Edit to add: It's made by the people that made Ruiner. The aesthetic and soundtrack suddenly make complete sense.