Returnal is a roguelite bullet hell sci fi shooter. The levels are randomly generated and only particular items/aspects carry over from each cycle. You go pew pew with various guns over and over and have to dodge seemingly impossible numbers of orbs, beams, and thrashings to reach the game's end and story's conclusion. As the protagonist Selene you are trapped in never-ending cycles after having crash landed on an alien planet. Only by working through these cycles can you overcome the creatures who stand in your way and uncover the secrets beneath the game's surface.
The game plays out over the course of 3 acts, which are comprised of 6 levels called biomes. The first three biomes comprise act 1, the second act is comprised of biomes 4-6, and the third occurs after the first credits roll. In this act, you are able to free roam either cycle (1-3 or 4-6) and unlock a hidden ending, which adds more layers to Selene's story and an interpretive twist.
Returnal challenges you to master its gameplay mechanics. If you are unable pick up it's nuances you're likely not going to have a good time. Many of the game's systems and aspects are somewhat obscure at the get go and only over the course of repeated cycles do they become more clear how they connect and can be exploited. Each aspect requires strategy and at times measured risk. Rushing in without making use of every tool at your disposal can result in a quick death/restarting the cycle.
Just when you feel like you're getting the hang of it, Returnal throws the challenge of forcing you to not get too attached to guns/set-ups that you acquire during a great cycle. There's no guarantee of getting the same items or weapons cycle to cycle. As I exalted in defeating the third boss and felt powerful with my setup, I devolved into frustration as I realized I lost those items as I started the second act.
Over time I became flexible to different items and weapons and my skill with the game's mechanics grew. I became less dependent upon upgrades and healing items. I went from dying repeatedly to running full cycles consistently and am now one collectible away from the platinum trophy.
Returnal is not a game for everyone. It unapologetically won't hold your hand. It challenges you to make the most of each situation with what's readily at your disposal. If you overcome its challenges and master its mechanics you'll be rewarded with a great feeling of accomplishment and be privy to have experienced the entirety of a great tightly made game.