Returnal has a system that’s far from unique to Roguelikes, but it’s an interesting one all the same. Parasites. These are tiny alien bugs that you can pick up and attach to the protagonist. They both enhance her and cause a debuff, but they’re worth picking up. These little guys might not seem important to a run early on, but by the time you’ve got to get through three biomes before you can comfortably face a boss, you’ll want to be dripping in them. The thing is, you might not know that until you’ve died a few times for really dumb reasons in a run.
Parasites can affect literally anything in Returnal. They can increase the chances of you picking up a malfunction, and they can boost your damage if you have a malfunction. They can make it so that using keys causes damage, but they can also increase the number of resources you gather from kills. Some of the debuffs are more powerful than others, and you have to weigh that up each time you encounter one. Luckily, there are plenty of opportunities to pick Parasites up.
In my most recent run, I had at least five Parasites on the go at once. I took damage from falls, so I was careful to never fall, and enemies produced acid pools when they died. However, I was earning more resources, so I could buy more upgrades, dealing more damage, and had a stronger suit because of them. Some of my Parasites fell off after a while because of the type of buff they provided, but they helped me get through three biomes relatively unscathed.
I’m telling you this because initially, I totally ignored Parasites. I didn’t see the point in giving myself a debuff for a run, just in case it was the best run of my life. However, after playing for a few more hours, Parasites made total sense to me. Housemarque is incredibly good at making a specific type of game, and the Parasite system has been tweaked to make that type of game even better. I don’t know what Returnal would be like without Parasites, but I can tell you now that it would be a lot duller.