I'm not sure what I was expecting when I started playing Gunpoint, but it surely wasn't a puzzle game. I thought it was going to be a neat little 2d shooter with some platforming spliced in and an interesting story. I realized pretty quickly that it was a mix of stealth and puzzle more than anything. Great stealth and puzzles.
The goal in each level is more or less the same - get to a thing and then get out. Guards will patrol some areas - or stay in place - and you have to go past them without alerting everyone. I love that it's not instantaneously game over if you get spotted, but you take very few fire before you die. A thing Gunpoint does great is the option to restart 1, 5, 10 or 15 seconds ago when you die. Think you just messed up a simple move? Restart 5 seconds ago! Think you planned everything wrong and must start over? You can do that too! Some variety in the objectives could've been nice but then again you have secondary objectives each stage (get laptops, kill everyone, harm no one) so I won't complain too much.
Your basic way of sneaking in an out is by re-wiring everything in the buildings you have to infiltrate. A locked door can't be opened by yourself, but if you rewire it to a light switch, you might be able to open it. Motion detectors, cameras, alarms, elevators, even guns, you can rewire a ton of stuff to anything else, creating complex machines where a guard flipping a switch might cause an elevator to go down, activating noise detectors and opening a timed door. It's great stuff, even if a bit confusing sometimes when a ton of stuff is happening at once, but at least time freezes when you're using the rewiring tools.
The upgrade system is a bit weird, you get money and points for completing missions, but they're pretty useless. I either wish you wouldn't get upgrades or that they did more. When I saw the revolver, I thought I would be able to blast through the rest of the game, but using it triggers an incredibly difficult police sniper to spawn and murder you on sight, most of the other upgrades are only useful in very specific occurrences - and thus don't change the way you play the game, which makes them feel like they're required to make some parts of the game easier. Also the skill points can only be spent to boost your jumping pants and your battery, I barely used the battery stuff.
Oh yeah, you have crazy spring pants too, that's a bit weird, I feel like the game would've worked perfectly without them, but okay, why not! I really loved Gunpoint, all things considered, being able to sneak around because you're a master at puzzles - and not at crazy split-second perfect timing - feels really good and the story kept me going forward.