Yes, I'm still playing it, and at this point I can honestly say that I have sort of a "love-hate relationship" with this one. Though I often call it "love-loathe", because I can. Admittedly, I tend to have this sort of opinion about MANY games. Even Starward gives me that feeling every now and then. Which is made worse by the fact that things irritating me in that game are often of my own design, haha.
But anyway, I'll go into some detail here to help you make a decision:
The game makes an AWFUL first impression, to be honest. This is something I heard from a couple of other people I know that bought the game and didn't refund it (there are then others that I know that bought it and DID refund it). The game starts out with a HUGE amount of content locked, including every single NPC that isn't the main shopkeeper (and he runs what has got to be the single most uninteresting shop in the entire genre). This honestly seems like a bad idea to me as it's these other special rooms and NPCs that keep floors from becoming too repetitive. And some of these special rooms (pretty much all of them, really) can be pretty interesting. NPC vendors tend to sell useful stuff, and a couple of them work in unique ways; there's one that sells items for keys instead of money, and the items he sells tend to be very good, but keys are precious things so the decision to spend is a tough one (and thus, interesting). There's another one that sells a variety of really powerful things, that aren't too costly.... but that give you a hefty dose of Curse whenever you buy something from her. If you don't already know, Curse is a hidden stat that tends to up the game's difficulty. As Curse rises, Jammed enemies (faster, tougher versions of normal enemies that fire "jammed" bullets that do a full heart of damage instead of half a heart, they're very dangerous) appear more and more often, and even Jammed bosses can appear if it's high enough. The amount of ammo drops goes UP, but the amount of every other type of drop goes DOWN. You tend to get more money also. If Curse hits 10, it's max, an unkillable, powerful Reaper-like enemy spawns, and he NEVER EVER GOES AWAY. Literally follows you from one room to the next, constantly firing spreadshots. He'll even get in the way when you're trying to use the shop (which makes the shopkeeper yank his items off the shelves and run away). So, Curse can be really deadly, but the stuff you get from it can be very worth it. She can even sell items that generate more curse themselves, which means that you get a really NASTY dose of it by buying said item from her (going up to, say, 5, with a single purchase). Powerful items... but again, a difficult and thus interesting decision. NPCs and special rooms in the game tend to be like this. And anything that adds interesting decision-making to a roguelike is a GOOD thing... but when you first play the game, it seems like it has NONE of it, because of the sheer amount of locked things.
The unlocking process is slow, but mostly easy. NPCs are nice and easy to unlock; if one of their holding cells appears on a floor, somewhere on that same floor there will be an enemy holding a golden key, you just find the key, and unlock their door, talk to them, and you've unlocked them. But it's random as to wether or not a locked NPC appears on a given run. And even once you've gotten them, certain specific NPCs (2 of them, I think) have many of their items locked, which must be paid for with Hegemony Credits (dropped by bosses, they're used to unlock items in the Breach, which is the area you're in before actually entering the main Gungeon). The unlocking process can be satisfying, yes, but it's pretty darn slow. This further tarnishes the game's initial impression.
The game is also HARD. It's hard to quantify difficulty though, really. Or at least, it's hard for ME to do it, because I tend to think everything is easy. This is the case with this game too, but I call it "HARD" because most people find it to be the case. You're probably going to die a ton of times, over and over, before ever reaching the Dragun, the 5th floor boss. And that boss isn't even the true final one (the 6th and final area needs to be unlocked though, and that process is complicated, as you might expect from this genre).
As I learned more about the game, and also as I started to unlock more and more things and got the NPCs unlocked, the game really started growing on me. It became more and more enjoyable as possibilities opened up. Which is rather similar to what happens when starting Isaac, for that matter (as Isaac takes a very similar approach and locks the hell out of like 70% of the game's content).
Enemy designs are pretty interesting, with cute yet deadly (and also very memorable) characters as your foes. The game doesn't use true bullet-hell patterns like Starward does; it's often described as bullet-hell by people, but these are more "traditional" patterns. However, it has a FOCUS on these bullets. For comparison, Isaac has plenty of enemies that fire bullets at you, but it also then has a fairly equal number of enemies that attack via methods that fire no bullets whatsoever. In Gungeon, damn near everything fires bullets at you in some pattern or other. You have a dodge roll maneuver you can do to help you avoid enemy shots; it involves invulnerability frames, so you're encouraged to dodge INTO bullets (to pass through them) rather than away. The game actually tells you to do this, you don't have to figure that bit out by yourself.
Bosses I'm more conflicted on. They can be fun, but they take WAY too freaking long. The game has a tendancy to give things a bit too much HP; this is most noticeable against bosses, which can be a bit of a slog if the RNG has given you crappy guns. The Dragun is by far the worst example of this, having the most HP in the game, as far as I know. Even Lich, the true final boss, doesn't seem to have as much as that thing does. Wether or not the bosses are fun is going to really be up to individual player preference. Some players really like them, some do not. The good thing is that none of them use "broken" attacks.... with one very, very specific exception, but I'll not spoil that or why I think it's a broken attack. Chances are, when you reach that point, you'll know it when you get hit by it. That's fine though, it's VERY difficult to completely avoid busted attack patterns in a game like this, and it's something that can be fixed later should the devs decide to do so. Other than that one attack though, all others are fine.
Items and such: There are... screwball balance issues with the game. The worst bit for me is that there are a good number of items that just seem to have minimal "impact" on the game. For example, a suit of armor that doesn't give you defense, but gives you the ability to deal a good chunk of damage by dodge-rolling into enemies. As you might expect in a game where nearly every foe uses ranged attacks, this is... often not a good idea. It's an item that you'll find, and while it TECHNICALLY has an effect, it sorta feels like it doesn't do anything at all. There's a few too many items like that for my liking. Guns can be the same at times, but not as much. There are a few genuinely bad guns, but for the most part the game keeps them fun and interesting (and weird). A TON of weapons and items are also references to various things from pop culture and such. Stuff like the Proton Pack from Ghostbusters (which works exactly like it does in the movies), or the Polaris, a reference to the Polar Star gun from Cave Story, with the exact same "level-up" mechanic as in that game. TONS of things like that. Guns tend to be fun to use even if some of them are genuinely bad. The game does sort of make some weapons items SEEM really bad until you learn what they can really do for you. The T-shirt Cannon is a good example. Seems bloody terrible at first; does very little damage. Until you realize what it's very heavy knockback can do for you; using it to shove powerful, high-HP enemies into one of the game's many pits kills them INSTANTLY; I often buy this weapon and take it through the entire game for this purpose. But it can take quite some time for the player to figure out things like that.
And like any Roguelike, it has what I call "obscure" mechanics. The sorts of things where you don't know about or understand them fully without consulting a wiki; or things that blatantly show up, but confuse the hell out of you when you find them the first time (like the Demon Head Door, for instance). For example, the whole "curse" thing, or the confusing "coolness" stat (another hidden stat that's important), or the method of opening secret rooms.... provided you can find them. Or the strange way of entering the Oubliette, a secret level that can often be important, and the decision of wether or not to go there in a run... once you've figured out how to open it... can be a tough one. I cant think of a game in this genre that does not do this "obscure" sort of thing; even Starward, which we tried to keep straightforward, has mechanics that fall into this category, for example the screwball way that secret rooms are opened. So that's not really a "problem" to me. There is a very extensive wiki for the game, so you can look up anything that is confusing or weird. It's often a good idea to do so when you encounter something new.
So, overall, if you think the game looks appealing, I'd say, give it a try. Just be aware that it wont be as good initially, but it will become a lot better later; you just need a bit of patience to plow through to that point. And as I said, the game is HARD. It also has a lot of RNG to it... you'll see what I mean if you do play it. Expect some frustration, though that's not TOO out of character for this genre, no sir...
Oh, and find the wiki and look up the different types of treasure chests before playing. Just so that you're aware of the different rarities rather than looking at the chest's color and not actually being sure wether it's a good one or not.
Also look up how to make the Bullet That Can Kill The Past (in the game's story, getting this bullet along with the Gun That Can Kill The Past is the central goal of all of your characters, and the entire reason why everyone wants to delve into the Gungeon). You HAVE to do this to get further than the Dragun (among other things that the unlock will do for you), and the game really doesn't hint much as to HOW to do this. You only need to do it once, over the course of multiple runs (not all in one run). It's probably the single most important unlock in the game.
Last tip: DO NOT leave ammo boxes lying around to be grabbed later. Ammo boxes are extremely important.... but if left in a room, this Rat guy will appear, when you're not in the room, and steal it. It's possible to catch him in the act and make him appear to go away, but unless you grab the thing immediately after doing so, he'll just wait for another opportunity and come back and grab it. He will also take any active items that you leave behind, but he will not pick up hearts or keys, so it's safe to leave those for later. And yes, there IS a reason to leave keys behind temporarily; it guarantees that the shop on that floor (if you haven't already found it yet) will have at least one key to sell. If you've already found the shop on a floor, there's no reason to leave keys behind to be picked up later.