Sonic Robo Blast 2 and Mystic Realm are two of the greatest Sonic fangames ever made! Go here to download, read, and learn about them:
http://en.wikipedia.org/wiki/Sonic_Robo_Blast_2
Main site:http://www.srb2.org/
I’ve tried them but I always found them to not feel that ‘sonic’ to me. A lot of work has been put into them but since they use the doom engine and have no loops or even slopes it just doesn’t seem right to me. (Mind you I’ve never liked the 3d sonics as much as the 2d ones.)
I personally prefer Sonic Mettrix (stealth.emulationzone.org/) which is just about a complete clone of the old 2d games.
Sonic games are absolute pants these days, it all went downhill after Sonic Adventure. Mmm, I loved that game.
Although a certain someone I know is taking a strong liking to Sonic Shuffle… <<
Sonic Adventure was awefull in my opinion. I’ve never played a more broken game.
To each their own opinions. I found it was quite enjoyable, though. Racing the clock to gain emblems was quite an enjoyable challenge.
SRB2: Mystic Realm is great apart from the second level in the Sky Sanctuary type zone with Sonic. That level is H-E-L-L. One misplaced jump and it’s goodbye you. The bosses could have done with more variety too.
Sonic Adventure 1 rocked, Sonic Adventure 2 was very good. Heroes was shit and Shadow was alright at first, but got boring later. Haven’t tried Riders yet.
I enjoyed SA2 to a small extent merely because I liked some of the Sonic/Shadow levels, but in my opinion it was hugely flawed due to:
i) how the levels would just continue on from one another, no ‘action fields’ (is that what they call them?) in-between.
ii) Tails being stuck in some walker thing. That was awful, and Tails was a pretty enjoyable character in SA1.
iii) The overall length of the game. Very easy to complete in a day, unfortunately.
I stopped buying Sonic games after SA2. I got somewhat sick of Sega in-general from that point onwards, too.
Sonic CD all the way BABYYYYYYYYYYYYYYYY!!!
You don’t have to tell me. There were plenty of times where I wanted to blow up the game, because it was so challenging, but that’s what made it so addictive. Don’t give up, just practice the jumps and layout of the levels.
Also, in Sonic Robo Blast 2, when you get Super Sonic, it rocks! While in a jump, if you hold the spin dash button, you can hover. It’s just cool. 
legaia flame - Your avatar scares me.
I know, I get that a lot. I like it though.
Yeah, another thing we agree on (like the queen ^_^)
I liked SA1 and SA2
SA1 was just amazing, SA2 got a tad boring at times. Completable in 1 day i heard??? ahhh 180 emblems is still on my “to-do” list (also just 3 more races away to complete MSR!! looks at arcie )
But yeah, best part of SA2 was the Chao 
ahh adds finishing website to to-do list
Music was good in both games however… not really tried any new sonic games
oh yeah Sonic Shuffle rules, great board game with 4 players
I’ve got it; it’s rather disapointing. I would rank it about equal with Sonic Heroes. I enjoyed Sonic R (that was the one good Sonic racing game), but - like Heroes - I felt that Riders doesn’t give you enough control over your character. The idea was interesting, but a number of things ruined the game for me unfortunately.
Haven’t tried Shadow yet…
You can try me any time you want. 