For most scripts I found D,A,P,%ARG provided everything needed. If you fully understand how to use these and the obvious MOV, MOVR, ESMALL, ELARGE, LARGE, SMALL, EQUAL, INC, SUB, MUL, DIV and ! you can do anything with logical thinking. %INPUTSTR, %INPUTNUM are useful occasionally too. Advanced scripting I used readvaluesql and writevaluesql a fair bit. N scripting.... here's an example of use:
#ACT
GOTO @start
[@start]
#SAY
Welcome to Mir Slots.\
How much do you want to gamble?\
<10 Gold coins/@gamble(10)>\
<100 Gold coins/@gamble(100)>\
<1,000 Gold coins/@gamble(1000)>\
<10,000 Gold coins/@gamble(10000)>\
<100,000 Gold coins/@gamble(100000)>\\
<Chickened out/@exit>\
[@gamble()]
#ACT
MOV D0 %ARG(1)
GOTO @gamble2
[@gamble2]
#ACT
TAKE Gold %D0
MOVR D1 3
MOVR D2 3
MOVR D3 3
MOVR D4 3
GOTO @gamble3
[@gamble3]
#IF
EQUAL D1 %D2
#ACT
GOTO @twoway
#ELSEACT
GOTO @showreelslose
[@twoway]
#IF
EQUAL D2 %D3
#ACT
GOTO @threeway
#ELSEACT
MOV N1 %D0
MOV N2 3
MUL N1 N2
MOV D5 %P9
DELAYGOTO [local] 1 @showreels
[@threeway]
#IF
EQUAL D3 %D4
#ACT
MOV N1 %D0
MOV N2 12
MUL N1 N2
MOV D5 %P9
DELAYGOTO [local] 1 @showreels
#ELSEACT
MOV N1 %D0
MOV N2 6
MUL N1 N2
MOV D5 %P9
DELAYGOTO [local] 1 @showreels
[@showreels]
#ACT
GIVE Gold %D5
#SAY
Reels: <$output(D1)> <$output(D2)> <$output(D3)> <$output(D4)>\\\
CONGRATULATIONS, YOU WON <$output(%D5)>!!

\\
<Play again?/@start>\
<I've lost enough/@exit>\
[@showreelslose]
#SAY
Reels: <$output(D1)> <$output(D2)> <$output(D3)> <$output(D4)>\\\
YOU LOST

\\
<Play again?/@start>\
<I've lost enough/@exit>\