PowerSlave, aka Exhumed, is the name of two games with two names (actually three, including the Japanese name). The Playstation and Saturn versions got a modernised port/remaster recently, but they're quite different to the DOS game, which is the version I recently finished. It took me a long while, partly because I started playing using DOSbox with dated controls, before switching to a source port. I found it to be refreshing compared to other 90s shooters, and it has a few interesting features that I think help it stand the test of time.
I will start by saying that the gameplay is well designed. The weapons are mostly useful, although I did stick to just the machine gun and pistol for most of the game. Ammunition and health pick-ups are plentiful enough to make the experience fun but scarce enough to encourage exploration and just the right amount of weapon swapping. Platforming and puzzles are mild, but not mind-numbing. They aren't too repetitive either, or at least not in a boring way. The level layouts are interesting and not often frustrating, although the game does strictly follow the "hunt for the keys" structure that was common at the time. Overall the gameplay elements add up to an entertaining experience.
A few aspects of Powerslave stand out compared to other (semi-3d) games from the time. One is that weapons have to be reloaded. This is done automatically but it breaks up the action, forcing you to duck for cover or change direction when an enemy is no longer flinching from taking damage. The game also features a few different items, all of which consume a magic meter. There's a power up that increases fire rate, an item that heals the player, a torch for dark areas, and an invisibility powerup. They're not the most innovative items but again, they break up the gameplay a bit. The boss fights are really cool too, being divided into multiple phases and taking place in dramatic arena areas.
There are some really cool details in this game, like the different death animations. Whenever the player dies there is an animation with their hand falling in front of them, and it changes depending on the kind of damage they take. Another detail I liked was the rats that hang around darker areas. They don't harm the player but you can kill them or just watch them run around. It's a good looking game too, with lots of cool outdoor areas with water features and somewhat realistic structures, and a hint of environmental storytelling here and there. Actually there are quite a few sections where the player needs to dive into waterways and swim underwater. It reminded me of those underwater areas in Tomb Raider, maybe "Tomb Raider meets Doom" is a good way to describe this game.
I definitely recommend this one, especially if you are getting a bit bored of Doom and Duke Nukem, but (like me) haven't spent too much time with other 90's FPS games.