In short:
Surreal setting and intriguing plot with roguelike die-and-start-over gameplay and fluid, polished FPS controls and camera.
Lacks the growth and progression of many roguelikes, making many play-throughs entirely wasted, and the game inaccessible if you lack hyper twitch skills.
More detail:
Mystery right from the start, in a surreal world with a surreal premise, and the intrigue is cleverly built into the rogue-like gameplay, with gradual reveals as you slowly unlock more areas and abilities and discover more secrets. It's dark, creepy, and the lightning, soundtrack, and sound effects combine well.
It's the first FPS I've seen that's a roguelike, and I expected it to be poorly implemented. But the controls are smooth, both in movement and shooting, and the camera is easy to control. Areas where combat starts allow for a wide range of tactics, with natural cover, potential for chasms or other drops to maintain distance, and often ways to get higher or lower than the enemies.
You might have to be familiar roguelike, rogue-lite, metroidvania style games to properly enjoy the semi-repetitive nature of dying and restarting over and over and over again. But honestly, that's what makes them such addictive games. Most 'runs', you'll unlock just a little more to make the next run easier. It could be a stat boost, a gear upgrade, or a more unique ability that gives you access to shortcuts and new areas. Whatever it is, that constant little increase in achievement just feels so good.
Unfortunately, while it looks like there are going to be tonnes of different things to unlock and to discover... the difficulty level can be a significant barrier.
In most other roguelikes, the difficulty is extreme to begin with too. But in many, as you replay over and over, you grow in minor ways that ultimately lead you to reaching a level where you can manage. That makes each play-through feel rewarding, even if you die right near the end of a level or after getting tonnes of abilities and power ups - because you know that even though you missed out on that try, you're a fraction closer to success next time. In Returnal, each death just feels like a complete waste, because all the relevant investment and growth is reset each time.
Importantly, within each run most of the game mechanics are designed to only award perfection. Three primary examples are:
1) The healing items
double as max health increases, except you only get that max increase if you don't use it as a healing item. That is, the only way to increase your max health is to never get hit, otherwise the items are wasted in simple healing instead.
2) All weapons have a 5-stage power up that is entirely dependent on not getting hit. One of the power ups is a considerable increase in the resource used to gain access to higher level weapons. If you get hit, the power up resets, so your progression will be too slow to ever reach higher levelled weapons.
3) Another of the power ups is having an additional weapon ability, such as firing off a range of homing pulses in addition to the main ammunition. If you get hit, it resets back to just the main ammunition.
In summary of those three points: if you get hit, you lose out on a range of benefits and bonuses that will prevent you from levelling up properly during that run, in numerous ways. As a result, you'll be more likely to get hit again, and the cycle repeats. The overall impact this has is that if you get hit once or twice, you can be sure that run will be wasted, so you may as well die right there and start afresh. Perfect play or restart, perfect okay or restart, perfect play or restart...
Final comment:
Another in a string of games that are hard for the sake of being hard. Except in this case, it's otherwise an amazing, intriguing, addictive game. That makes it all the more painful to have to let it go afterixx cd you get stuck in an endless loop of dying with no benefit.
