That requires loops to be efficient with the memory.
Repeat K=45 //repeat until the exit option is selected
Menu("Level","1-25",1,"1->50",2,"1-100",3,"Exit",X) //select which level
45->K //trigger the loop to exit
Lbl 1 //Location tag for the generator to reference for each level
10->L //number of guesses in the level
1->A:25->B //set what the Internet must be between, inclusive
Lbl G //start the game
Delvar L1 //clear the list
SetUpEditor L1 //start the list
RandInt(A,B)->I //generate the number
Repeat Dim(L1)=L or G=I //repeat until all guesses are tried, or the correct answer is guessed
If not(sum(G=L1) //if g is not in L1
G->L1(dim(L1)+1) //add it to L1
Disp "You have already guessed that!" //otherwise, they already guessed it
Disp "Good Job!"
Disp "Sorry, try again!"
Delvar K Delvar L1 Delvar A Delvar B Delvar G Delvar I//cleanup your variables
Disp "Thanks for playing!"
That should get you started.
||Variable tested to see if the user wants to exit
||1; sets lower bound for number generation
||Sets upper bound for number generation
||List 1; records numbers already guessed