LONESTAR

I've played through 5-6 games, and each run felt very different. For example, one game I got a strength buff for being under 10hp, and then I got an event to trade Max HP for shield. So I dumped all the max HP and I was cooking. I haven't found the difficulty curve to be too hard. I think I have like a 75% win rate, and I'm now on the 5th ascension. But it's not a cake walk, and you will often need to prioritize gearing up for the next fight over taking long-term scaling. In the first couple of fights, you are maybe 10% stronger than the enemies, and if you don't scale up fast, they will overtake you.

As a Con, some of the descriptions on the abilities aren't great, and it's a game where understanding how exactly mechanics work is very important. There is an encyclopedia, and when it's descriptive enough it's great. But there are still some gaps in how things are explained.

I will premise this by saying: I feel this is a game moreso geared towards those well-versed in roguelikes and/or deck builders already. It lacks an amount of prettying polish that leaves it a little rough around the edges, with boring visuals and a story so forgettable I couldn’t for the life of me tell you what it’s about other than “spaceship fights”.
That being said, the mechanics and QOL pieces in this game give a die-hard roguelike fan a great game to dig into. The concept is simple: place the numbers you draw each turn into your lasers to increase their power. Make your number bigger than your opponent’s to deal damage. There’s all sorts of different ways to get to that beautiful churning engine point that we all love in these types of games- using positioning of your guns, or even your ship; accruing treasures (relics) to augment your ship; and even upgrading your numbers to draw bigger and better ones are just a few ways to make a winning strategy. You really hit a big “a-ha” moment the first time you generate a flood of energy all in one turn.
I strongly appreciate that this game’s per-run progression is heavily altered from the typical Slay the Spire map feel that’s becoming a little too pervasive. You have to fight 4 enemies per galaxy for 3 galaxies to win a run, and it’s always in the same difficulty curve of enemies each galaxy. It has a wide enough variety of enemies and bosses though that you don’t feel like you’re facing the same ones over and over, and different enemies really force different strategies- sometimes even remapping where your guns are to optimize for a fight. In-between enemies, you have a number of vacation days to spend on various events, mixing up the traditional branching tree navigation of roguelikes.
The three ships you can use aren’t too different from one another, but there’s a ton of captains you can use, with some unique to their ship type. I haven’t used anywhere near all of them, and some seem pretty lackluster to top tier options (Dango all the way baby!), but with as many options as you have, it’s inevitable some won’t make the cut. Though it is nice to have some that are wildly different playstyles for replayability!
There’s a meta progression system, pretty standard for the genre. You unlock new captains, new units, new treasures for succeeding. As you keep winning, you unlock new difficulty levels (your ascension levels), and they really provide a challenge as you climb the ranks.
The part I really want to point out is the various QOL features in the game. As someone who doesn’t put in the effort to mod games, there are a lot of small fun things I feel you’d normally have to add in yourself. For starters, all the damage you and your enemy are going to take/deal is very clearly displayed. The UI is fairly simple, making for a nice and easy to learn experience- and an excellent Steam Deck game! There’s an in-game save scum feature that just lets you retry a fight with no penalty. As someone who admittedly has done so in many a Slay the Spire run, just offering a quick reset button if I make a stupid misplay or want to try a boss again adds to my willingness to push the difficulty in this game. There’s also an optional post-game boss rush where you fight several bosses back-to-back with no healing in between. As someone who’s often sad at the end of a particularity busted run, it’s awesome to have a little victory lap when you’ve got that beautiful 1-turn-kill ship up and running.
To summarize: overall, I think if you've sunk tons of time into Balatro, FTL, Slay the Spire, Hades, or any number of other rogues and are looking for something new, Lonestar is a great little game that’s designed for you. I don’t think it’s in my all-time greatest hits of the genre, but it’s absolutely been a great way to fill the gap while waiting on something else big and new to come out. I can see this being a pick up and put down rogue I’ll keep coming back to every now and then, and definitely recommend it for us devoted roguelike fans!

If you like slay the spire, and also are not annoyed by lane mechanics, this is a reaaaaaally good game to pick up. The nature of the energy generation and the arsenal management is really satisfying, managing to create interesting engine potential in a single player rouge-like while removing some of the insanely salt inducing low-rolls of traditional deckbuilders.

A fun roguelike.
Instead of cards or dice you draw machines for your space ship. Machines can be placed into a limited number of slots along three lanes. Their placement can influence your power in that lane (that you'll try to use to overpower the enemy in that lane) or have side effects on adjacent machines, usually in a specific direction.
Battle rounds consist of you getting a random amount of three types of energy, though you can influence your 'deck' of energy. You'll try to match that energy to your machines, converting or amplifying it, feeding it to your weapons to generate power or to special machines for extra effects that can modify the base rules of engagement.
In all three lanes your power is then compared to the enemy power, and the loser in each lane takes damage depending on the power difference.
Each run, you'll face several enemies from a roster of enemy types; each type has special rules that you have to adjust your semi-random loadout to.
A single run is good for half an hour or so of fun, though you can exit-save after each fight. Which makes it a great brain-teaser for easily manageable chunks of fun.

it's not really a deckbuilder, it's an engine builder - there are no cards to draw, just pieces that interact with each other. That said, it's an engine builder where the creators absolutely understood the assignment. This is fun to play over and over and over again, and the huge variety of pilot characters gives the game some real staying power.

This game is amazing. I want to say it is a cross between Slay the Spire and FTL, but it isn't really either of those things at all, so that is helpful I am sure. You pick from a number of pilots (each with their own special ability plus two other random abilities each run), grab from a few different ships, and run at three different zones with 2 normal enemies, a sub boss, and an end boss each. Each one enemy gives you some coins, a weapon or other ship mod, and some "treasure" which is usually some kind of passive bonus to combat or vacation or shopping or whatever. I can't recommend it enough!

The build variety in this game is some of the best I've ever seen! The replay value is very good and you rarely get to reuse previous strategies / cookie-cutters.

Very often, the 9-unit limitation on your spaceship is super frustrating -- until you realize that it's a key element of the game design. Once you accept that it's meant to force you into making tough decisions (e.g., "is this rapid-scaling legendary attack unit better for the overall build, than this common support unit that buffs everything else?"), you can really start to appreciate the gameplay loop.

This focus on decision-making also applies between battles, where you get to spend "vacation days" on stuff like shopping, repairs, upgrading, and random events. Once again, you have to weigh your options as you (typically) don't have enough vacation days to do everything.

Also, don't be deterred by "scary math" that I saw mentioned in some of the other reviews. There's no more math in this game than any other roguelite deckbuilders. There's a great preview system that clearly shows the effect of any given move in a round, and you can restart a battle as many times as you want with no penalty.

There are 9 difficulty levels. I have beaten them all with one of the three ships so far, and have yet to actually lose a run. This doesn't mean the game is easy though, but I do spend a lot of time overthinking my decisions and frequently use the "restart battle" feature on the higher levels. If that's not you, lower difficulties are equally rewarding and enjoyable; I typically play on difficulty 7 or 8, as I find 9 to be a little too sadistic for me. (especially if one aims to solve the mystery of the universe.)

tl;dr: buy this game if you like being challenged by big-brain deckbuilders and don't mind the relatively strict constraints that prevent you from snowballing into OP-livion.