Okay, so you should put your INPUT in a loop.
WHILE
INPUT "",T$
IF T$="blah" THEN GOTO @BLAH
IF T$="blah" THEN GOTO @BLAH
WEND
This way, if it doesn't go to a label, it will just ask for the input again.
do you know what the help button is? it's the blue question mark button in the top-right. use it while the cursor is on SPHITRC to get a usage summary.
optionally, you could use SPHITRC, which also requires a SPCOL but uses a rectangle instead of another sprite. you could use this with TOUCH OUT to not even have to use a cursor!
erm
SPCOL is supposed to be called before the SPHITSP is called, and only once.
So
DISPLAY 1
SPSET 0,255
SPSET 1,21
SPCOL 0
SPCOL 1
IF SPHITSP(0,1) THEN ?"HIT"