Action Biker – A great 8bit game gets an enhanced version by Grue

Ask anyone about the 8bit game of Action Biker, and they’d probably tell you it was not only a great game with an awesome soundtrack, but there was nothing more fun than riding about on a motorbike, collecting various items, while avoiding all sorts of obstacles. Well this famous game hasn’t just made a special appearance on our site, but thanks to Grue however, there’s also been an enhanced version further improving an already great game.

And here’s the latest from the creator via the Lemon64 forums. “Why Action biker? There is already a good versions of it around, but I wanted something more, so I decided to look into it! Basic stuff: crack the original, reverse engineer the game, and generate sources. The game itself was pretty straightforward. I didn’t even bother using the Ghidra for the reverse engineering part and proceeded straight into the 6502 bench. The game map is 160 x 80, or 4 screens wide and 2 tall. The bike uses 32 sprites for its animation, and the map tiles fits into one font. The playfield also has a Z-axis, so the player can move up or down some of the features, which are handled using unique tiles on the map”. 

“The gameplay consists of collecting items on the map, which upgrade your bike so you’re ready for the drag race at the end of the game. Some items have noticeable changes, like collecting a gearbox, which allows you to switch to lo/hi gear using the fire button. I added some more functionality for the items; here are the changes I made”:

• Petrol gauge – activates the fuel bar on the screen
• Exhaust pipe – change the bike sound
• Speedometer – displays the speed
• Brake lamp – activates the brake lamp on the bike
• Go faster stripes – more max speed for the bike 😉
• Water skis – you die if you drive on the water under 50
• Stopwatch – activates timing of the drag race

“I also added time measurement to the drag race. Time is measured between changing the start light to green and the finish line. If you have a better time than before, it gets saved on disk. Also, HighScore is saved if you manage to get one. There is also PAL/NTSC detection mainly for the race clock and the screen split timing. 6581 and 8580 gets also detected and filter cutoff is adjusted to fit better”.

More of less the complete list of the changes:

• – Start a new game with a fire button instead of using the keyboard.
• – fuel level is not shown until the petrol gauge is collected
• – Changed “press space to play” text to “press fire to play”
• – Item called “go faster stripes” changes max speed $fa -> $ff
• – Speedometer on screen, activates when the player collects the speedometer 🙂
• – Border flashing on death tidied up so the raster line colors are changed is $00, not $40
• – Changed collision detection with a fence so it won’t crash until actually touching the fence
• – Implemented toggle for F7 – key, music now off and back on
• – I added Brake Light, and the sprite layer was activated after collecting: tadaa! brake lamp
• – Added race time display, activates after collecting stopwatch
• – collecting exhaust pipe activates lowpass filter on channel 3 (sfx dedicated)
• – count time from green light to finish line. Show the result on screen when reaching the finish line.
• – die if moving under 50 on water with waterskis
• – fix a bug where you could ride under 50 at large parts of the lake.
• – The original game didn’t have to kill bits on all the water tiles.
• – Build number and some credentials on the title screen.
• – added pause key, use run/stop for pause.
• – Sid detection and change filter cutoff value depending on 6581/8580, affect the exhaust pipe sound
• – high score and best time save/restore
• – NTSC fixes, timer change for 50/60hz refresh rate, and screen split tidying up depending on the system.
• – if you run out of fuel, flash fuel text on the screen with the border.
• – fix a bug where the game always started at time: 10:01 instead of intended 10:00
• – mute sid during fileops to avoid hearing hanging notes
• – disable filter on voice3 on game over, to enable 3rd voice on the game over tune.
• – fixed a bug: if you crashed during the race, race timer wasnt stopped and reset on retry.
• – Unused tables and variables removed and gaps in memory optimising
• – NMI setup to rti

And there’s all there is to say about this enhancement, so come and check it out (HERE)