[This is a review of Version 2.2.8, though I also played... I believe Version 2.0...? around 14-15 years ago]

Depending on how you define the term, my favorite Sonic fangames are Sonic Mania and Sonic 2: Special Edition. But assuming you don't count those (and, like, fair), then my favorite is Sonic Robo Blast 2. Without question, one of the greatest games to feature Sonic, over much of the official series.

Honestly, a lot of my appreciation for this game comes from how unlikely it all sounds on a high level. Even knowing how high-octane DOOM can be, I neeeever would've guessed at a well-realized, non-gimmicky Sonic game making sense in that engine. And yet...

I love 3D Sonic, but I'll be quick to point out that the post-Adventure games have pretty different design philosophies from the classic series. Yes, Sonic's always been a spectacle platformer series, but the means by which you get there changes. 2D Sonic places more focus on methodical exploration, with speed being a reward for good play; 3D Sonic encourages speed as often as it can, with speed built into its strongest set pieces. Exploration is traditionally presented as being divorced from speed in 3D Sonic...

(I haven't played Sonic Frontier yet, so no idea how the open world design addresses that)

...which is what makes Sonic Robo Blast 2 so striking. The game very cleanly blends 2D game design into 3D space. Levels are HUGE and expansive to accommodate the player's innate desire to explore, with a huge emphasis on naturalistic or logical environments. Sure, you still have plenty of video gamey obstacles like spinning spike bars and death lasers and such, but there's usually some sort of logical continuity to how the player explores the Zones, which in turn informs the cadence of challenges.

And it's not a complete rejection of 3D Sonic's design, either! A lot of the environmental storytelling you see in some of the Adventure titles and especially Sonic Unleashed, where the progression through biomes and buildings communicates its own adventure, gets teased out in SRB2. "Castle Eggman" isn't just a string of castle-themed rooms. It's a long trek through a forest leading up to the castle, followed by a trip through several rooms and libraries, followed by a run across danger-riddled castle ramparts. "Egg Rock" isn't just a generic space zone, but rather a slow infiltration of a meteor base as the player dives into the heart of Robotnik's stronghold. "Arid Canyon" is more than a generic desert level, it features a race through an abandoned mine and down to a train robbery.

Now, it isn't uniformly this - Greenflower and Red Volcano in particular are largely just biomes without any sort of adventure progression. But then, the game's still under development (even after twenty-five years of continuous work), and plans exist to embellish these levels and add more to boot. So, maybe some day! Even so, even with the game as it is, it's a very easy, very strong recommendation from me. Great stuff.

Miscellany:

- It is insane to me that this Sonic fangame off the DOOM engine spawned a Kart-Racer, which itself spawned a Persona dungeon-crawler. To parse this: a first-person shooter was modded into a third-person 3D platformer, which was modded into a racing game, which was modded into a turn-based RPG. It's hard for me to even wrap my head around that.
- I LOVE THE BOSS OF ARID CANYON. GREAT PULL HOLY CRAP
- Since I played different versions, it was kinda funny watching the plot go from "Eggman blew up a mountain, ANGST" to "Eggman Roboticized a mountain, oh but don't worry, people are okay (or at least will be once you beat the video game)"
- Theming the bonus rounds after NiGHTS into dreams... is a cute touch. Doesn't feel too far off from the realm of possibility, given the inexplicable NiGHTS cameos across some official titles and the Chemical Plant boss from Sonic Mania
- I haven't even played a Dark Souls game, but I love what that little sword-and-fire communicates in Castle Eggman.
- I think I tried the multiplayer once? Got dissed in text-chat for not knowing what I was doing, and decided I was good.
- Sonic's Speed Thok sure is a weirdly-named move, but it's a good compromise for the Homing Attack, itself a compromise for Sonic's speed in 3D. I like how much utility the move gives you, offset by just how much of a commitment it is. Good solution for something to give Sonic, to give him a movement counterpart to Tails' flight and Knux's gliding.

Over 25 years in development and it still has potential.

If you're looking for the traditional Sonic experience you won't find it here. SRB2 brings a unique precision platforming spin on Sonic gameplay, bred from the limitations of the Doom engine. While a fun experience, I feel like it has potential that hasn't yet been realised. It's still rough around the edges in terms of polish and accessibility, and many players still find it exceedingly difficult. Nonetheless, it's a fun experience and I'm glad to have spent so many years playing and making mods for it.

One of my 3 favorite games of all time, and easily the best Sonic game of all time in my opinion.

I've been playing this since i was like, 10 or something, back when Vista was the current Windows OS... so I admit, I'm ridiculously biased:

The game perfectly translates 2D sonic into a 3D space, the bright colorful world with simpler 3D graphics makes everything look beautiful and charming. The music isn't the best I've ever heard, but it's fine and works well!

Controls feel great. Your characters move fast, but are also easy to steer, so turning corners and rounding obstacles won't be difficult. On top of that, since it's in 3D, you can see hazards coming from a mile away and adjust. But at the same time, exploration and free movement around the level is possible and incentivized, to find items, medals, and access to special stages.

The mods and fan made characters/levels are insaneeeeee. Especially if you're open to older versions of the game: You have an insane backlog to try. But if you don't care, the main campaign is a fun level-based romp with plenty of platforming and running to do.

The way vertical camera movement works is odd and not the best, but you don't really need it to be. Left-Right camera movement is perfect and will get you through the levels just fine.

I could write an essay on this game, I genuinely love the hell out of it.

It can run on a potato. it's a game that's been available since like, almost 20 years ago . You have nooooo excuse. Try it!