RONIN

It's alright, I highly recommend buying this on sale. Although this game has some interesting ideas and concepts, it lacks polish and has a few Quality of Life issues that makes it hard to enjoy sometimes.
A 7/10 on sale, 6/10 if you pay full price.
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As someone who has been wanting to play this for years and is currently playing Ronin's "New Game Plus", I'd like to offer a more detailed review into this intriguing, yet somewhat disappointing game.
A More Detailed Review
That's the short of it, now let's get into the details. This game is not a stealth game, rather it's a game where you bring a sword/katana to a gunfight.
The Story
You are a near-perfect hand-to-hand combat fighter on a singular path of revenge against the company members and friends who killed your father and took over his conglomerate. You face no qualms about your murder spree, except for one level. You ultimately kill the boss of the conglomerate and either live or die when running away.
That's the extent of the story, told through some text on a picture right before you start the tutorial or a boss room. The bosses are unique in whether they stand in the middle of a room with a gun/sword or are in a room waiting to die/jump. The story is simple and effectively conveys the simplistic rage of the protagonist. Why else would you have to not only kill the bosses but also be recommended to kill all "enemies"?
The Gameplay
I'd say gameplay wise, Ronin (2015) is pretty similar, to Gunpoint (2013). It might even have been inspired by Gunpoint to an extent. Both games focus heavily on similar jumping mechanics. In both games, you infiltrate a corporate facility that are (for the most part) guarded by better armed guards. It's expected, in either game, that you have to outsmart these guards through cunning and skill. The games diverge in how you do that and I'd say gunpoint is more fun, creative, and less limiting.
Ronin does not focus on hacking nor rewiring electronics. Its focus is to stab and crush any enemy in your way, and that's where Ronin flourishes. You get to pause time in order to commit to insane maneuvers. Do you need to swing in through the window, kill the guard standing there, and throw your sword at the machine gunner in two seconds? That's what pause does for you, alongside the abilities you earn throughout the game.
You earn these abilities by adhering to these optional goals on each level. Don't worry, they're all the same and don't matter for the final level. If you: Kill all enemies, spare all civilians (don't worry, most levels don't have them), and don't trigger the alarm. The first goal is self explanatory, kill everyone who has a sword or a gun , in most levels the second goal doesn't apply, and the last goal is the only one a player should worry about. All you have to do with the third goal is be attentive and either knock out or kill the person trying to trigger the alarm. If you fulfill all three goals, you get a skill point. If you get skill points for all levels leading up to the final level, you have all the abilities provided for the game and needed for "New Game Plus" - if you want to do that.
The abilities are interesting: throwing your sword, h@nging someone, stunning everyone for two seconds, setting a decoy, teleporting to said decoy, teleporting in front of an enemy. Most of these abilities are incredibly useful one way or another.
The fights are very much focused on momentum, which you can get by stunning an enemy (by jumping at them) or killing an enemy. You lose momentum over time. You usually lose your momentum points by playing an ability (h@nging is an exception) or by getting to much and having an extra turn.
The extra turn is useful but it feels wrong to be punished by being successful in the core loop of the game . Also, believe it or not, you are actually locked out of some abilities if you have too much momentum - which doesn't make sense nor is it fun.
Say you hack and slash a couple of guards and you really need to kill this enemy by throwing your sword (a lower point ability) instead of just teleporting to them ( a higher point ability), you are locked with the latter in this system. This leads to a lot of people deliberately losing momentum in order to access lower useful level abilities - which directly goes against the core loop of gaining momentum and killing people as quickly and creatively as possible?
How about instead of this, abilities don't get locked due to high momentum, don't punish the players for playing the game?
Lack of Polishing
Let's talk about bugs
Enemies and players can get stuck in walls. It's clear how it can be annoying to the player. However, this can be a boon to speed runners if they can figure out how to get to the other side, which they have. More problematically, enemies who are stuck no longer have a line of sight on the player. They then can trigger the alarm at a safe spot.This is game breaking. If the game encourages you to kill all enemies and avoid alarms being triggered, you cannot have enemies and players getting stuck in walls.
Checkpoints and Level Saver
This is especially the case with the weird checkpoint systems and the lack of a level saver. There are not any clear checkpoints or even text notifying that you had reached a check point. Additionally, you cannot have more than one checkpoint in a level. Which means that if you want to go further back in a certain level than the most recent checkpoint, you can't - meaning you have to restart an entire level.
Speaking of leaving a level, level progress is not saved. So if you want to take a break from a given level, you have to stay in game in order to keep your progress. Essentially, you have to finish each level in one take. This is astonishing. There isn't much more I can say about that.
The Problems with Jump-Through Platforms
Moving beyond that, we have issues with jumping and platforms - two things that aren't important in a hack and slash platformer. If you are trying to jump through a platform that you are supposed to jump through, chances are that can't jump through them even though the jump trajectory clearly tells you that you can.
The developer lampshades this through one of their "tips" : Jump arcs can lie . In my playthroughs with this game, I have not encountered that issue at all - unless if it is jumping through a jump-through platform. The game has a hard time discerning that jump-through platforms are not necessarily solid platforms and the developers haven't patched that. This may be harsh, but if you want people to use jump-through platforms, make them jump through-able.
Machine Gun Aiming UI in "New Game Plus"
In "New Game Plus", machinegunners do not simply shot in a straight line for a few seconds. They actually react to where you move. This makes the mode more challenging, in a satisfying way. The game doesn't change the UI to reflect that.
Recap
So let's recap. Ronin is an interesting, tactical platformer that primarily focuses on fighting. The story is simple but serviceable. It makes some questionable choices when it comes to the core game loop, sacrificing parts of it in favor of less exciting mechanics.
The game also lacks polish and has some noticeable bugs that further get in the way of playing the game. This all would be much more tolerable if it wasn't set at the price it's at. I've gotten this at sale and I'm have a hard time seeing past its flaws. Other people here are having similar problems.
It's especially disappointing in the sense that this game has a lot of potential. If you look at games that are similar in gameplay (Gunpoint) or thematically (Mark of the Ninja), Ronin could have been a lot better with more polish. Perhaps it would have even be worth buying at full price.

Mark of the Ninja meets Gunpoint. If the controls were tightened up (often you jump or grapple when you mean to attack, wasting your turn and getting you killed), if the game was longer, and if it didn't have the absurd difficulty spike on the second to last boss, I'd say this is an underrated classic. As it stands however, it's simply a cool idea executed in a somewhat mediocre way.
Every day I wish Steam would add a "at price point" for reviews; I would not buy this game full price, however it's definitely worth a fiver or less and will keep you mostly entertained for it's short run (at least when its not making you tear your hair out).

I don't think I've ever played a game that feels this satisfying, one of the only games that I come back to over and over again and never get bored. It's not super long and there are a few bugs regarding collision but overall it's just a wonderful experience to play.

I've completed the game with all achievements in 13 hours and gotta say, what a great experience. The combat is really unique and later levels will have you strategize a lot. As for what other reviewers are saying about performance, controls and so on, i have never had a problem with any of those. Definitely give this a try if you like puzzly stealth games or turn based strategical combat.

RONIN is a great game. I wouldn't recommend it at full price, but if it's on sale, it's a great pickup. It has an amazing soundtrack and gameplay that feels rewarding no matter if you choose the stealthy assassin gameplay or go in guns blazing. Furthermore, the new game plus mode offers an extremely difficult challenge for those who just want more after beating the game, making you use every single crumb of your arsenal.

Control for selectable objects is inconsistent at times, but it is a good time

Finished it. Didn't get to the happy ending though, but still, a pretty decent game. Sometimes the movement and movement indicator doesn't exactly match despite me not hitting anyone, so this inconsistency was a bit annoying, especially towards the end but that might just be me sorta rushing through the levels to try to be as stealthy and as fast as possible.

Game was surprisingly short though - By the time I reached the boss, I had thought I was only about halfway through the game due to the amount of people in the photograph the player character uses, BUT imo despite it being short, I actually think the length of the game is good enough because I'll be frank - I was getting a little frustrated and impatient with the mechanics of the game near the end.

Good game still, i'd give it a 6.5 though, maybe even a 7.