Critical Mass by Aerosmith guitar tab (text):

Critical Mass
(Tyler/Hamilton/Douglas)
 
     Many of the guitar parts in this song are backwards. I haven't 
 transcribed those because I haven't the slightest idea how. I have
 transcribed (most of)the regular guitar parts though. Have fun with them
 and write me with any comments,questions, corrections and additions.

 The chords during the verse just sound like G and A

     G   A
   
 E---3---5--|
 B---3---5--|
 G---4---6--|
 D---5---7--|
 A---5---7--|
 E---3---5--|

     G
arriving in boats, black hooded coats
     G
tormentors climbed into my room
         G 
i crawled under my bed, covered my head
             G
but they're flushin' me out with a broom
     G
the leader, she's small, pinned my ass to the wall
       G
for my seeds or she'd be losin' her past
A
time after time, she'd be readin' my mind
        A
but she never got the feelin' to last
G
celebrate, celebrate, celebraid it
G
this is the critical mass

so far so good, I heard the other say
so good so far, they're takin' me away
I drink to you, your mind, her ass
we'll take a drink and break the glass

celebrate, celebrate, celebreak it
this is the critical mass

 The first interlude and the second interlude are very similar guitar-wise.
 This is the second interlude:

 interlude(w/harmonica)
 E------------|------------|-----------|------------|
 B------------|-------10-9-|-----------|-------10-10|
 G------------|-9p7--------|-----------|-9p7--------|
 D--9p7---7-9-|-----9------|-9p7---7-9-|-----9------|
 A------9-----|------------|-----9-----|------------|
 E------------|------------|-----------|------------|

 E------------|------------|-----------------------|
 B------------|-------10p9-|-----------------------|
 G------------|-9p7--------|-------7-9---9--11-12\-|
 D--9p7---7-9-|-----9------|-9p7---7-9---7--11-12\-|
 A------9-----|------------|----(9)5-7---7--9--10\-|
 E------------|------------|-----------------------|


G(verse chords same as above)
now the tallest of two, with a brush full of blue
paints surrealist scenes on the wall(fill)
 fill 1(w/distortion)-
 E----------------------------|
 B----------------------------|
 G----------------------------|
 D---3------------------------|
 A------5---------------------|
 E---------3--6b-r--3--6b-----|

so I tell her for fun, that it's really well done
but she just ain't listenin' at all
she points to my heart, tellin' me if I'm smart
I'll practice and phase
out and admit, when the shoe doesn't fit
and I went screaming out down the hall

need it
need your love

just then I heard a poundin' on the door
we're all here, sang the voice of twenty more
I drink to you alas, we'll take a drink and break the glass

celebrate, celebrate, celebreak it
we are the critical mass(interlude w/harmonica)


time and space, is takin' me away
time erase, don't know the time of day

outro(slight variations)-
 E------------------------------------------------|
 B----------------------17b-----------------------|
 G------17-17p15-------------15b--r------17-17p15-|
 D--17-----------17-17---------------17-----------|
 A------------------------------------------------|
 E------------------------------------------------|

 E----------------------------|
 B---------17b----------------|
 G--------------15b-15--------|
 D--17-17---------------17----|
 A----------------------------|
 E----------------------------|

continue with similar, fade out

fade in with guitar part(maybe backwards) that sounds similar to this: 
 E-----------------------------------------------|
 B-----------------------------------------------|
 G---------0--------0--------0-----0-----------0-|
 D------------------------------------------0----|
 A------2--------2--------2--------------2-------|
 E---3--------3--------3--------3-----3----------|

fade out with backwards guitar and sound effects

Symbols used in transcription:
p = pull-off
b = bend
r = release
\ = slide