Shadowgrounds is an overhead shooter, wherein you shoot lots and lots of aliens in the face while wandering through maze-like buildings. This tried-and-true formula is foolproof as long as you can bring the goods (solid gameplay), and indeed, these kinds of games were pumped out at an incredible rate in the old days. While Shadowgrounds is a decent game, I think it suffers from a few recurring shortcomings.
Shadowgrounds uses a 3D rendering engine with a viewing frustum. The camera is suspended in the air, looking almost straight down, and the player is locked to the bottom-center of the screen. In turn, the camera rotation is locked to the player's direction, so that your firearm will always be pointing straight ahead. (There's a freelook mode that behaves more like a traditional overhead shooter, but I didn't bother with it much.) This setup is more technically advanced than classic overhead 2D, but I feel it introduces problems with visibility. There are beams over most doors, arches holding together tube-like passages, stacks of crates positioned for tactical assistance, and the occasional horizontal pipe spanning the upper-section of a room. You cannot see through these things. Many doors have a blind spots directly behind them, thanks to these beams. Tall stacks of crates can partially hide monsters. And these blind spots vary depending on your position, because of perspective. Now, one *could* put a bunch of view-obstructing things into a 2D overhead shooter, but most developers *didn't*, at least to that extent.
You get numerous weapons, which I think are all pretty good, but the game won't autoswitch to another weapon when your current one is out of ammo! Fumbling with the number keys or mouse wheel while getting swarmed by aliens is very frustrating, and several weapons run empty for long stretches. The pistol gets infinite ammo, so you can always fall back on it, but you have to click for every shot, against enemies that take multiple hits to die. Sometimes I switched to pistol when I ran out of ammo with some other gun, just because I knew it would work, but owmyhand. I also had issues with the shotgun sometimes not firing after a reload.
By the way, you'll want to upgrade those weapons as soon as possible. These aren't just modest improvements to your arsenal: many weapons can be upgraded to deal double damage very early on. I stupidly ignored the upgrade system until the first boss kicked my ass.
Shadowgrounds' enemies are pretty much excellent! They appear in large swarms, crawling out of vents and climbing up cliffs, and some of the more powerful ones force open doors during scripted sequences. Many behave differently if you cast light on them: one type of spider shies away, another lunges in anger! Some are big dumb idiots that walk directly towards you, others strafe between shots and try to keep away from you. Some can turn invisible, and can only be revealed using the light (...okay, those guys are kind of annoying.) Boss design I felt was a bit overbearing and difficult to get the hang of at first, but decent. Good stuff all around.
Movement is smooth for the most part, but you can get caught on props and the corners of walls. Nothing game-breaking, but it can leave you vulnerable. Your allies block you when you're trying to backpedal from aliens (argh!). You can quickly dodge with the space bar, but not when wielding certain heavy weapons.
The progression format is a sticking issue for some people. The game saves only at the beginning of missions, and you have a limited number of lives. Die, and you'll respawn at a checkpoint. After five deaths, it's back to the start of the mission. There's no quicksave, no "save & quit". I personally had trouble with one of the checkpoints, which kept placing me in a donut-shaped room filled with armored monsters I hadn't encountered before. I died and died until I realized that they were susceptible to grenades. Having said that, I never had to completely restart any mission, but I sure would have been pissed if that happened. Did I mention that the missions are fairly long? :)
To sum up: 3D perspective + architecture occasionally hampers visibility, weapons are problematic, movement is a bit unreliable, enemies are great, and the save system is pretty demanding.
