Procedurally generated is a dirty word in indie gaming, if you can't be bothered to create a carefully crafted difficulty curve, let the game decide for you instead and the other dirty word is roguelike where literally starting again is a gameplay feature so let's look at three of them.

Robo Quest

A young hacker girl finds a robot guardian in the middle of the desert, he gets fixed up and sent into battle to find out what on earth happened to humanity and why robots are hostile, of the three games, it's the simplest to get into and easiest to adapt to as you'll find yourselves making progress in no time.
A-Tier Game

Gunfire Reborn
If you took the Monster Hunter Cats and give them guns, you'll get something along the lines of Gunfire Reborn, there's less story to work with but the mechanics are tighter despite being the harder of the two FPS titles. It also has some of the best looking guns in the genre.
A-Tier Game

Neon Abyss
A 2D arena Roguelike where you defeat hell like carnations of modern era issues, the game tasks you with being more resourceful as every run requires you to build your character's arsenal from scratch with little to no permanent perks, the controls are a little awkward and the game is great at screwing you over at various points, despite it's faults it's a solid game.
B-Tier Game