this is one of my favorite online games, its probably the best online shoot em up ever.
there are two versions of it,
http://www.saydesign.com/games/ablast_shockwave.htm the version for shockwave.com, it has slightly better graphics, but runs slower on slower comps
http://www.arcadetown.com/ablast/index.aspI prefer this one, It runs faster, music changes every once in awhile and you transform after each boss
oh yeah, when a boss dies with a big explosion, get far from it, the explosion hurts too.
have fun :)