FROGGER

The game was originally going to be titled Highway Crossing Frog, but the executives at Sega felt it did not capture the true nature of the game and was changed simply to Frogger.

It’s possible to jump down and hop around in the reserve lives/timer area.  {Kristine Roper}

You can usually jump so that you are hanging off of the left side of a turtle, but not on the right side.

You can control the frog in the attract mode once it reaches the very top log.

If you play this game on a PC emulator (such as MAME) and use a code for unlimited time, you will hear the entire background song to its finish. This was never possible on the actual arcade game since you always ran out of time before the song finished playing.

There is a kill screen of sorts.  A level will appear where the top-most row barely moves.  This situation can only happen in Round 5 - the most difficult board. The board usually doesn't start like that but transitions to that setup.  It's not random but very predictable; it's the transition itself that is completely random. The first time you'll see the pattern is somewhere between 40K - 120K, depending on your skill level. You need to have put the 1st frog in the leftmost home. If the board transitions and you haven't done that you will have problems.  You may escape, but will lose 2-4 frogs if you're lucky to have that many left.

BUG: It’s possible to control the frog during the attract mode.  When you’re on the top row of logs, the game is always checking to see if you’re jumping into one of the homes.  Unfortunately the programmer(s) didn’t first check to see if a game was in play and just check the player inputs anyway. Oddly, there is some code immediately before where it jumps to that, that does this check.  {Phil Murray}

BUGPart of the background music will cut-out from time to time, only leaving the primary melody playing.

BUG: Collision-detection is not pixel-perfect, but as you can be jumping in the x-axis whilst vehicles are moving in the y-axis, it does an ok job of it.  But on the river you can make perfectly good jumps to the end of the turtles or logs and still die.  The game sets up a table for each row of moving objects (logs, turtles), and stores the x-position of the right-hand edge of the object. The actual position stored is 2 pixels right of the edge of the turtles and 4 pixels right of the edge of the logs.  It then tries to work out if you are on any of the objects by using the width of each object and seeing if your frog is in that right-to-left window.  If it is, then all is good, but if not, you’re in the water and you die.  So it gets the far right location slightly wrong, the width of the object is too small, and it bases the compare point for your frog at the right-hand edge of it which causes all sorts of errors.  {Phil Murray}

BUG: Sometimes the lady frog is invisible (normally purple) until you accidentally jump on it. Then she appears white with red legs on the frog's back. You still get 200 points.

BUG: From the middle section between the river and the road, jump upwards to a pad and jump back so where you have been moved to the left just a few pixels. You should be able to go off-screen to the right.  For more fun, jump upwards to where a pad should be.  You will make it, but you will die.  The x-position of your frog is $10 ($=hex) when on the left hand edge of the screen and $E0 when on the right hand edge.  When you jump, you move in multiples of $10 pixels so your position will always be $n0.  But when you’re jumping around in the water and land on a turtle or log, you move by 2 pixels at a time.  So your x position may not be $n0, but instead $n2, $n4, etc.  The game only checks to see if you are greater than $20 if jumping left and less than $E0 if jumping right, so e.g. if your x position is $DE you can now jump right to $EE which is off the right of the screen.  Likewise left, if your x position is $1E you’re not at the far left of the screen but it doesn’t allow you to jump any further left.  {Phil Murray}

BUG: Sometimes you die for no apparent reason.  It’s been suggested there are “invisible snakes” or other enemies on the logs that kill you.  I don’t believe that’s true.  There are 2 almost identical collision-detection routines that run dependent on which stage you are at in a vertical jump.  It sometimes gets the calculation wrong as to which row of objects it should be checking against, so if for example you’re on the very right hand edge of the top turtle row then jump up onto the log above, it calculates you’re still on the turtle row, the turtle has gone from beneath you and assumes you’re in the water and you die.  {Phil Murray}

BUG: Moving left and right on the very top log can sometimes be very slow.  It has nothing to do with previously eating a fly.  The game reads the player inputs, then directly afterwards is the routine to perform the frog movement.  The bug where you move slowly happens if you try to jump when you are below one of the homes and it has already been filled.  The game checks to see if the home is already filled and prevents you from jumping into that home again, but it brute forces it by simply not checking the player inputs (so also stops the movement from progressing).  So trying to jump left or right just before when you’re directly below an occupied home will start the movement, then it will stop it whilst you are below the home, then start again when you are clear of it causing the odd stuttered movement.  {Phil Murray}

BUG: When timed just right, if you jump into a home base that has an alligator and the alligator disappears mid-jump, your frog will die but will also make it home safely!  The game may also glitch at this point where you advance to the next screen, but the game will be running very fast and ‘frozen’ (unable to play – video #1).

BUG: Sometimes you can make it home safely and still lose a life (video #2).

 

   

 


Return to main menu