Game 8 Unit 13 of 16 1 hr learning time

Difficulty Selection

Let the player choose Easy, Medium, or Hard before the game starts.

81% of Minefield

Mark as complete Completed!

Hardcoding 10 mines works, but different players want different challenges. A difficulty menu lets them choose.

The Program

10 CLS
20 PRINT "Choose difficulty:"
30 PRINT
40 PRINT "1. Easy   (5 mines)"
50 PRINT "2. Medium (10 mines)"
60 PRINT "3. Hard   (15 mines)"
70 PRINT
80 INPUT "Choice (1-3): "; d
90 IF d < 1 OR d > 3 THEN GO TO 80
100 IF d = 1 THEN LET n = 5
110 IF d = 2 THEN LET n = 10
120 IF d = 3 THEN LET n = 15
130 CLS
140 DIM m(8, 8)
150 DIM s(8, 8)
160 LET r = 1: LET c = 1
170 LET s(1, 1) = 1
180 LET f = 0: LET w = 64 - n - 1
190 REM place mines
200 FOR i = 1 TO n
210 LET y = INT (RND * 8) + 1
220 LET x = INT (RND * 8) + 1
230 IF m(y, x) = 9 THEN GO TO 210
240 IF y = 1 AND x = 1 THEN GO TO 210
250 LET m(y, x) = 9
260 NEXT i
270 GO SUB 500
275 LET r = 1: LET c = 1
280 GO SUB 600
290 GO SUB 700
300 REM game loop
310 PRINT AT r + 2, c * 2; INK 4; BRIGHT 1; "[": PRINT AT r + 2, c * 2 + 2; "]"
320 LET k$ = INKEY$
330 IF k$ = "" THEN GO TO 320
340 GO SUB 600
350 IF k$ = "q" AND r > 1 THEN LET r = r - 1
360 IF k$ = "a" AND r < 8 THEN LET r = r + 1
370 IF k$ = "o" AND c > 1 THEN LET c = c - 1
380 IF k$ = "p" AND c < 8 THEN LET c = c + 1
390 IF k$ <> " " THEN GO TO 420
400 IF s(r, c) <> 0 THEN GO TO 420
410 LET s(r, c) = 1: LET w = w - 1: BEEP 0.05, 15: IF m(r, c) = 9 THEN GO TO 800
420 IF k$ = "f" AND s(r, c) = 0 THEN LET s(r, c) = 2: LET f = f + 1: BEEP 0.05, 5
430 IF k$ = "f" AND s(r, c) = 2 THEN LET s(r, c) = 0: LET f = f - 1: BEEP 0.05, 5
440 GO SUB 700
450 IF w = 0 THEN GO TO 850
460 GO TO 300
500 REM === calculate counts ===
510 FOR r = 1 TO 8
520 FOR c = 1 TO 8
530 IF m(r, c) = 9 THEN GO TO 590
540 LET g = 0
550 FOR i = r - 1 TO r + 1
560 FOR j = c - 1 TO c + 1
570 IF i < 1 OR i > 8 OR j < 1 OR j > 8 THEN GO TO 582
580 IF m(i, j) = 9 THEN LET g = g + 1
582 NEXT j
584 NEXT i
586 LET m(r, c) = g
590 NEXT c
595 NEXT r
598 RETURN
600 REM === draw grid ===
610 FOR y = 1 TO 8
620 FOR x = 1 TO 8
630 IF s(y, x) = 0 THEN PRINT AT y + 2, x * 2 + 1; INK 5; "."
640 IF s(y, x) = 1 AND m(y, x) = 0 THEN PRINT AT y + 2, x * 2 + 1; " "
650 IF s(y, x) = 1 AND m(y, x) > 0 AND m(y, x) < 9 THEN PRINT AT y + 2, x * 2 + 1; INK 6; m(y, x)
660 IF s(y, x) = 1 AND m(y, x) = 9 THEN PRINT AT y + 2, x * 2 + 1; INK 2; "*"
670 IF s(y, x) = 2 THEN PRINT AT y + 2, x * 2 + 1; INK 3; "F"
680 NEXT x
690 NEXT y
695 RETURN
700 REM === draw HUD ===
710 PRINT AT 0, 0; "Safe:"; w; " Flags:"; f; " Mines:"; n; "  "
720 RETURN
800 REM === game over ===
810 FOR y = 1 TO 8
820 FOR x = 1 TO 8
830 LET s(y, x) = 1
840 NEXT x
842 NEXT y
844 GO SUB 600
846 PRINT AT 13, 6; INK 2; "BOOM! Game Over"
848 BEEP 0.2, 0: BEEP 0.2, -3: BEEP 0.3, -7
849 STOP
850 REM === win ===
860 CLS
870 PRINT AT 8, 8; INK 4; "YOU WIN!"
880 PRINT AT 10, 6; "All safe cells revealed"
890 BEEP 0.15, 12: BEEP 0.15, 16: BEEP 0.3, 19
895 STOP

How It Works

Lines 20-70 present the menu. Three options with clear labels showing the mine count.

Lines 80-90 use INPUT to get the choice. The validation IF d < 1 OR d > 3 rejects invalid input and asks again.

Lines 100-120 map the choice to a mine count:

100 IF d = 1 THEN LET n = 5
110 IF d = 2 THEN LET n = 10
120 IF d = 3 THEN LET n = 15

Line 180 calculates the win target using n:

180 LET f = 0: LET w = 64 - n - 1

With 5 mines: 58 cells to reveal. With 15 mines: 48 cells.

Difficulty	Mines	Safe cells	Win target
Easy	5	59	58
Medium	10	54	53
Hard	15	49	48

Formula-Driven Difficulty

The mine count n drives everything. The placement loop runs n times. The win target is 64 - n - 1. The HUD shows n. One variable controls the entire difficulty curve.

This is better than copy-pasting three versions of the game. Change the mine count, and everything adjusts automatically.

Variable Name Gotcha

The neighbour-counting subroutine originally used n as its counter variable — the same name as the mine count. After the subroutine ran, n would be overwritten with a neighbour count instead of the mine count.

The fix: use g in the subroutine instead of n. Spectrum BASIC has no local variables — every variable is global. Choose distinct names for distinct purposes.

Try This

Fourth option. Add “4. Extreme (25 mines)”. That leaves only 38 safe cells on a 64-cell grid — brutal but possible.

Show difficulty. Print the chosen difficulty on the HUD: PRINT "Mines: "; n. The player should always know what they’re up against.

What You’ve Learnt

Menu input — display options, read choice, validate
Variable-driven difficulty — one value controls multiple systems
Formula design — 64 - n - 1 derives the win target from the mine count
Variable naming — global scope means names must be unique across subroutines