3rd Strike is a close call with 2nd Impact for one of the best Street Fighter games ever made, but it edges out with enough updates to presentation, mechanics, and new playstyles that make this an absolute must-play for fighters of all types.
If you've seen the other Street Fighter III reviews you get the general gist of the story, but 3rd Strike acts as a sequel of sorts to 2nd impact and includes extra updates such as Alex and Ken fighting Ryu, Chun-Li rescuing a kidnapped child, the appearance of mysterious new characters such as Q and Twelve, and Akuma and Oro almost kill each other! The characters get weirder and the playstyles resemble these new changes.
For example, Makoto's slow and methodical karate style works just enough to complement Ryu and Ken's styles, and Twelve's array of strange airborne moves feels at home in an anime fighter moreso than this title. Q's moving wall approach limits him to his dangerously powerful supers whereas Remy deals in very specific charge zoning and projectile heights. Tier placement is all over the place but characters are much more technically interesting than any other entry by far.
3rd Strike receives yet another aesthetic overhaul, with genres that dip into hip hop, drum & bass jungle, trip hop, breakbeat, and all sorts of goodness. It's easily one of the best soundtracks that Capcom has ever made. Portraits get an upgrade, a grade system gets added to push performance, the announcer and UI gets a deliciously cool update, and stages thunder with life and detail.
As for engine changes the changes are both slight and extensive in places. The red parry to parry from a block animation is a little too strict for most people to see but can help escape blocks from multi-hitting moves. Inputs for throws and universal overheads have been standardized for handy access for any fighter, and hit confirms are a little trickier to manage. That said, it's still possible to have a lot of fun at any skill level and parries (along with fun minigames for car destruction and basketball!) are still fairly doable.
3rd Strike's balance is still not quite up to snuff and some characters feel left out (Twelve's damage output, Sean's fall from grace) whereas some top-tier characters are a little too tricky to play to make it worth it (Yun's CC-style super, Makoto's throw stun) but in between there's a bunch of different fun characters to try and 3rd Strike is still exciting even 25 years from now. Give it a shot!