This game is just peak! Smooth controls, LOVE the character movement, the game is well optimized. The hook helps a lot, extra jumps save you a lot of trouble from falling down. save points and quick travel - super neat. coop - didn't try any - no friends to try that.
LOVE the terrain breaking system (got couple of upgrades by cheating the game with this, lol
THE BOSS BATTLES!!! SO COOL!!! HUGE MACHINES that you take down part by part - amazing! Arenas are very dynamic.

the only downsides I found:
-camera sometimes goes all around when you go up the walls and jump off
-weapon lvl up seems to be kinda extra...doesn't add stats or anything, really...I found only grenade launcher's upgrade useful

i need them to make a multiplayer spinoff with an armor class system and capture the flag as the main mode

While I haven't looked into NG+ and Rogue mode, everything about EPN I've experienced makes it a satisfying, compact experience. While learning to guide the shots of the weapons on offer might take a second, you eventually get into the groove of it, allowing you to enjoy a well-designed combat system. No weapon feels blatantly inferior to others in their weapon slots, even if some rapid-fire choices with bigger magazines often don't work as smoothly as alternatives with less aggressive ammo consumpton. That and admittedly sniper rifles, while effective and usable, do have some quirks in learning to use them compared to most of the arsenal.

While I mentioned it prior, let me emphasize - the game's movement mechanics are some of the finest I've known. Traversing the environments of both the main game and the Under the Clouds expansion are enjoyable and give you a sense of movement and speed without holding the player down, even moreso if/when the player decided to find the Agility Orb collectibles needed to upgrade their movement capabilities.

I personally appreciate the fact the game contains additional challenges and rewards for when you've completed the campaign itself. This keeps you engaged in what the game has to offer before you're done finding and gathering everything.

The story is, as admitted in the Under the Clouds expansion and its developer comments, less of a priority in EPN's design, and I will only state it is fine as-is.

EPN also has some wonderful environment design in both audio and visual aspects. One can easily get engrossed in the game's world as they zoom through either the floating islands or woods of the game's world.

What's not to love? Highly recommended for the price.