Similar to the way that your points accrue with each level that JumpMan completes, your program can 'remember' how long you've been playing and adjust the speed of play accordingly with a variable that changes the speed over time.

/* * Here, you'll add a difficulty setting which changes over time to make the * game more difficult. * * Changing the speed means editing how quickly the position update occurs. * To create a speed-changing effect, you will change how often position and * animation update, again replacing a number with a variable. */ #include "MakerScreenXVI.h" MakerScreenXVI lcd; byte run0[8] = { //legs in partial stride 0b00000, 0b01100, 0b01100, 0b01100, 0b01110, 0b01100, 0b01010, 0b01010 }; byte run1[8] = { //legs in full stride 0b00000, 0b01100, 0b01100, 0b01111, 0b01100, 0b01100, 0b01010, 0b10001 }; byte wall[8] = { //wall obstacle 0b11111, 0b10101, 0b11111, 0b10001, 0b11111, 0b10101, 0b11111, 0b10001 }; byte crash[8] = { //crashed JumpMan 0b00000, 0b00011, 0b01011, 0b00111, 0b00011, 0b00011, 0b00001, 0b00001 }; //The new icon for the jump part of the animation. byte jump[8] = { //mid-jump icon 0b00110, 0b10110, 0b01100, 0b01111, 0b01110, 0b01011, 0b10000, 0b00000 }; int position = 0; //holds the changing position of the cursor bool runState = 0; //which running animation to draw (0 or 1). int jumpState = 0; //0 ='pre-jump', 1 ='mid jump', 2='post jump' bool buttonState = 0; //will equal 1 after press, 0 after jump completed int wallPosition = 14; //wall can be placed from 0 to 15 int points = 0; //jumps without hitting a wall /* * Create two new variables to hold the durations of the animation * cycle length and the position cycle length. These being variables * will let you change the period of time between updates as the game * progresses. These variables will be checked against millis() and they are * measured in milliseconds. */ int animationDuration = 300; //ms between animations of JumpMan's legs int runDuration = 600; //ms between moving JumpMan's position on the screen long animationTimer; //tracks animation (custom character) updates long runTimer; //tracks position updates void setup() { lcd.begin(); lcd.backlightOn(); lcd.createChar(0, run0); //partial stride character lcd.createChar(1, run1); //full stride character lcd.createChar(2, wall); //wall character in 'slot' 2 of custom characters lcd.createChar(3, crash); //splatted character against the wall lcd.createChar(4, jump); //mid-jump icon pinMode(6,INPUT_PULLUP); //button to trigger jump //Start both timers equal to millis() so that the difference between //millis and the variables is 0. animationTimer = millis(); runTimer = millis(); } void loop() { lcd.setCursor(0,0); //upper left of the screen lcd.print("Pt: "); lcd.print(points); //Set the cursor depending on the state of the character if (jumpState == 0){ lcd.setCursor(position,1); } else if (jumpState == 1){ lcd.setCursor(position,0); } else if (jumpState == 2){ lcd.setCursor(position,1); } if (jumpState == 1){ //if jump has been activated.. lcd.write(4); //draw JumpMan mid-air } else{ lcd.write(runState); //draw the run0 or run1 animation } lcd.setCursor(wallPosition,1); lcd.write(2); //draw wall if ((digitalRead(6) == LOW)&&(jumpState == 0)){ buttonState = 1; //1 means a press is recorded } //Button is unpressed and a jump has been completed if ((digitalRead(6) == HIGH)&&(jumpState == 2)){ jumpState = 0; } // In the timer block for the animation, replace the 300 from // before with the variable animationDuration. if (millis() - animationTimer > animationDuration){ runState = 1 - runState; //draw the next JumpMan animation animationTimer = millis(); lcd.clear(); //clear the LCD to draw a new character } //Replace the 600 ms timer from before with the runDuration variable if (millis() - runTimer > runDuration){ position = position + 1; if (position == 16){ wallPosition = random(3,16); //place wall in column 3 through 15 position = 0; } //if button has been pressed and a jump hasn't been initiated... if ((buttonState == 1)&&(jumpState == 0)){ jumpState = 1; //signal a jump buttonState = 0; //reset button to 'unpressed' in the code } else if (jumpState == 1){ //true if jumpState set to one in the last loop jumpState = 2; //jump is marked as complete } // If the jump is missed, reset the duration variables and points if ((position == wallPosition)&&(jumpState != 1)){ points = 0; drawCrash(); runDuration = 600; //reset to 'level one' speed animationDuration = 300; //reset to 'level one' speed points = points + 1; } /* * Increase the speed and add a point whenever there is a successful * jump. Change the '...duration' variables here to get smaller with each * successful jump. */ else if (position == wallPosition){ /* * Decrease runDuration by 50 ms for each successful jump. * Decrease because the duration is the wait between updates- the lower * the wait, the faster the change. */ runDuration = runDuration - 50; /* * If runDuration gets too small, JumpMan will just be a blur on the * screen. Keep its value at a minimum of 100. */ if (runDuration < 100){ runDuration = 100; } /* * To give the appearance that JumpMan is running faster, adjust the * animationDuration so that there are two leg animations per change * in position on the screen. */ animationDuration = runDuration/2; //Move legs twice per position change } lcd.clear(); runTimer = millis(); } } void drawCrash(){ lcd.clear(); lcd.setCursor(position-1,1); //move cursor one position left of the collision lcd.write(3);//draw 'splatted' JumpMan lcd.setCursor(wallPosition,1); lcd.write(2); //draw the wall delay(1000); // Reset the variables to put the JumpMan back at the starting point position = 0; buttonState = 0; jumpState = 0; } /* * Again you have made your game more fun and flexible by using a changing * variable value in place of constant numbers- now this is starting to look * like a fun game! * */ //(c) 2017 Let's Start Coding. License: www.letsstartcoding.com/bsdlicense
 

Don't forget as you play with this program that none of the numbers we use are 'law' that you have to use in your game. For example, this program stops the runDuration from going below 100, but that was a subjective choice. You can play with those numbers and create your own variant of the game.