criterion:
if it works, you get to be a star
if you did the digit-at-a-time, you probably got a +

wolf:
adj1
af4 +
ajw2 --
alanyeung +
amh6
bc6
cbh1 + (there is a sqrt in gawk, and your . is dead)
cew4
chl1 + (nice rpn, arithmetic result should have implicit enter)
clh1 (nice, but some buttons lead to empty screen)
dfk1 (nice rpn, but some buttons lead to empty screen)
dmo1 (i liked the default-select of plus)
dst2 -- (ok, you get to be a star even though it doesn't work b/c novel)
emh4 (i tested your error checking!)
ewm1 (i found some arithmetic errors)
ihetu + (i got you on divide by zero... ++ worked well though)
jas6 (well, that's different, but not really genius... 00?)
jastraat + (i got you on div by zero!)
jdt1 + (wimpy clear button!)
jhdavis
jp1
jrb5 + (maybe my favorite -- like a sinclair! -- what does the prog do?)
jtd1 (i still want your ebay code...)
jy3 + (but i couldn't do a chain of calculations, e.g. 9+7*3-2=)
jyd1
jz7 + (i like the originality, and the modern layout of digits!)
kg3 + 
kkl1 + (couldn't chain my calculations)
kma1 + (ok, my new favorite.  the lexus of 4-function calculators)
mdc1 -- (similar to ajw2...)
nw4 + (arith result should have implicit enter, like chl1)
pas4 - (can't chain calcs... stealth calculator?)
ptd2 + (behaves nicely, although div by 0 is questionable) 
ram7 -- (credit for the wild buttons and the attempt)
sdb1 + (oh no, a stack calculator that requires two enters or binary ops!)
sk7 -- (evals too soon)
sz1 (reply? debugging output?)
ykp1


k9:

cls1 + (esp for div by 0 errmsg, plz rm your core, and isn't that a backslash?)
djfreima +
jjl2 + (stack behavior is a bit weird)
laz1 +
lz4 (interesting, well, hmm)
nch2 (novel submission idea)
nsr2 + (except for div by zero)