I don't want to say that the Alpha series struggled when it was new, but the first entry felt like graphically a step up, but maybe in some other ways a step down from where Street Fighter 2 had ended as a series. Street Fighter 2 started off as a series relatively impoverished in features and characters too, I suppose, and updates and tweaks made it better, but that was different. It was the first time this kind of game had been done, and we were forgiving of them giving us more as they developed it. With subsequent series, we kind of had high expectations from the get-go. However, every Street Fighter sub-series started off the same way, and wasn't really "worth" picking up until it was at or near the end of its arc. The Alpha subseries was even more unusual, because it overlapped with a different sub-series, the Street Fighter III game. Between the two, I always greatly preferred the Alpha series, and sales bear me out on this, however, there are some other reasons why this is true. Street Fighter Alpha III was ported to the Playstation, which was the most popular platform if not in the world (although I believe that it was) but at least in America. Street Fighter III got Dreamcast ports, because that was the only hardware that could support them, but the Dreamcast always underperformed in sales and was cancelled early. Street Fighter Alpha 3 had, at least in the console ports, all of the beloved characters from Street Fighter 2, but also added in a number of previously unavailable Street Fighter 1 characters, a number of characters from their also popular side-scrolling beat-em-up franchise Final Fight, and a decent collection of original characters that seemed to fit the vibe of the original characters fairly well.
That character selection was a major strike against Street Fighter III, by the way; not just its port to consoles that weren't as popular. The timing was also bad; the arcade boom that was in part facilitated by Street Fighter II was fading by the mid to late 90s, and people were more and more playing at home on consoles that for the first time could offer experiences as good as the arcade (mostly) with much more convenience and at a somewhat reasonable price. Not only did Street Fighter III start off with no returning characters except Ryu and Ken (and apparently, the developers were pressured into including them!) but even when it got "maxed out" with the Third Strike installment of the series, it still only had half of the characters that Alpha 3 had. (To be fair, it had Chun-Li and Akuma by then, and a few of the III characters have finally gone on to be fan favorites after a while.) But it wasn't just the character selection; the game mode and options selection was incredible for Alpha 3 on the home ports. Some of the modes were a little novelty feeling, and after trying them out a few times, you don't need to do them anymore (like Dramatic Battle.) The World Tour mode is kind of like a prototype for Street Fighter V's General Story, and is a welcome addition. It takes, like the Story mode, several hours to play, and once you do, you may or may not care about ever playing it again, but it's still a pretty fun mode while it lasts.
But Arcade mode is where it's mostly at with this game, of course. When playing, you select not just your character, but also his "ism." There are three choices here; X-ism in which your character plays more like a Super Street Fighter II Turbo character, with a single charging super move and better offensive capability in general at the expense of defense. The damage rating is increased somewhat, the defense rating is decreased, and air blocking and ground recovery are removed (because they weren't in SSF2T, after all.) V-ism is the counter to this; defense is increased and damage is decreased, and the super meter charges quickly, but you do "custom combos" that work considerably different to regular super combos, and do less damage. (The actual super combo moves can be pulled off as part of a custom combo, although the input for them is different, but they don't really do the same thing.) A-ism is the standard mode with the three-tiered super combo meter, the Alpha gameplay features and unmodified damage and defense ratings. If you unlock Hyper Alpha in the Alpha Anthology, you can even further customize this.
But in reality, while playing around with these options is fun for a time, I suspect most players settle on an ism that they prefer and just use that most of the time. I know that I do; I've never liked V-ism much, and while I'd played with X-ism a fair amount, A-ism as the standard Alpha gameplay experience is my greatly preferred option that I use 90% or more of the time. I feel like many of the characters are also similar to other characters, or have moves that may have worked great in an arcade cabinet, but are very difficult to pull off with a Playstation style controller. This means that some of that variety is a little bit illusory; it's there, sure, and you can select it, but realistically, are you really ever going to? I know that there are players who love to play with chargers, and their weird double diagonal charge super combos, but I find them extremely difficult to pull off on demand on a d-pad no matter how much I practice, and I have a similar issue with 360° motions; especially the 720s. I suppose some people invest in arcade sticks to play with, but those still aren't quite the same as an actual arcade cabinet even so. Sadly, this isn't an issue that I think Capcom have ever really seen as important, although finally in Street Fighter V, some of the use of motions that make sense on an arcade cabinet but not on a handheld controller have been minimized. Not eliminated, because that would no doubt offend the die-hards, but minimized.
And, of course, I have to mention the greatly improved look of the game. The stages were much better done from a technical artistry level, although as far as I know the technology for stages wasn't really the issue. The sprites were redrawn to look less like late 80s and early 90s video game sprites and more like comic book characters, with a kind of line-art outline around them. This style of sprite animation had previously been debuted in the Darkstalker game, and then the X-men fighter by Capcom. Sadly, they got better at it over time, so newer designed characters tend to look quite a bit better than the older, originally drawn sprites. Seeing Morrigan next to characters from Marvel vs Capcom 3 or Capcom vs SNK2 was almost embarrasing. The Alpha characters tended to hold up relatively well compared to the worst of the Darkstalkers characters, but ultimately, that was one of many limitations with using hand-drawn animated sprites for character models. The art alone literally took loads of man-hours to develop, like a hand-drawn animated movie such as Disney would make, and because the time and cost were prohibitive, they were re-used as much as possible.
Another minor gripe I have with the game is that the portable ports had four additional characters that for some reason never made it to the Alpha Anthology collection. I know, I know--they just ported the games as they were, but this seems just a little bit lazy to me. It's not necessarily like I miss most of those characters; three of them were in Capcom vs SNK 2 anyway, and the third is one that I don't know or care anything about because she only showed up in a lazy slapped together "let's throw together some sprites from a few different games and have them fight" release in the mid 2000s, when the genre was really mostly considered dead anyway. She kind of has the vibe of a filler SNK type character, in my opinion, and her inclusion in a handful of poorly thought-out games doesn't make her very appealing in general. As a bit of a throw away tribute, there is a cosplay alternate costume for Karin that looks like her in Street Fighter V. But other than that very minor niggling regret about the version I have, this is one of the best Street Fighter titles of all time, and as such, is of course, a contender for best of the genre. I think IV takes it still, but other than that one, this is a credible competitor, in spite of its age.