See YouTube video, for recording with sound.
Tank vs UAP is a 6502 machine-language arcade game for the stock unexpanded Commodore VIC-20. Tank vs UAP was inspired by the original type-in BASIC game, Tank vs UFO, by Duane Later. The original type-in game, Tank vs "UFO", could be found at the back of the VIC-20 user manual, along with a number of other games written by Duane Later.
Tank vs UAP retains the core sprit of Later's original Tank vs UFO, a single screen 2D tank trundling back and forth on the ground, shooting aliens out of the sky and dodging their bombs, ...but expanded, to offer a more arcade-like experience.
See also, Tank vs UFO 2.0: An assembly language rewrite of the D. Later's original 1981, BASIC type-in, Tank vs UFO.
- 🔎 Overview
- 🚀 Quick Start
- 🎮 Controls
- 💾 Loading and Starting
- 📂 Project Structure
- 💻 Building From Source
- 🙋♂️ Acknowledgements
- 📄 License
Just like in the original Tank vs UFO, you control a tank that patrols a single ground line at the bottom of the screen. However, unlike the original game, this tank is battling UAPs, instead than UFOs. Because, it's 2021, and the ODNI Preliminary Assessment says UFOs, are like, so 1981.
The main goal of Tank vs UAP was to create a pixel-smooth, arcade-style, interpretation of the original BASIC version of Tank vs UFO.
| Feature | Description |
|---|---|
| Pixel Smooth | Pixel smooth graphics and animation. |
| Non-Blocking Events | Non-blocking animation events. |
| Aimed bombs | Each bomb vectors from the firing UAP toward the tank centre, with the gradient clamped to ±1.0. |
| Crashing UAPs | Crashing UAPs pose a collision threat to your tank. |
| Progressive difficulty | The number of simultaneous UAPs scales with score, from 1 up to a maximum of 4. Surviving 4 UAPs is, challenging. |
| Arcade-Style Scoring | Arcade-Style score and high score. |
Want to just play Tank vs UAP? Download the disk image from the v1.0 release:
| File | Download | Use case |
|---|---|---|
tank-vs-uap.d64 |
download | Run in VICE, or load on a real VIC-20 via SD2IEC / Pi1541 / 1541 |
Run in VICE (unexpanded VIC-20):
xvic -memory none -autostart tank-vs-uap.d64
The
-memory noneflag is required. By default VICE enables a 3K RAM expansion, which relocates the BASIC start address and prevents the disk-loaded program from landing at$1001. Tank vs UAP targets the stock unexpanded machine, so the expansion must be switched off.
Run on real hardware (disk only):
LOAD "TANK-VS-UAP",8,1
RUN
Same game-play controls as Duane Later's original Tank vs UFO.
| Key | Context | Action |
|---|---|---|
Z |
In game | Move the tank left while held (44 px/sec, PAL-calibrated). |
C |
In game | Move the tank right while held (44 px/sec). |
B |
In game | Fire the tank gun vertically. Reloads for 250 ms before the next shot. |
| Any key | Title screen (boot only) | Start play. |
| Any key | Game-over screen | Start a new game instantly (high score retained). |
Tank vs UAP is disk-only for now. Tape is, unfortunately, not 'yet' supported.
Put tank-vs-uap.d64 on an SD2IEC, Pi1541, or 1541 Ultimate (or write it to a real floppy for a 1541 drive) as device 8, then at the BASIC prompt:
LOAD "TANK-VS-UAP",8,1
RUN
LOAD "*",8,1 also works — the main program is the first file on the disk.
The VIC-20 must be unexpanded (no 3K / 8K RAM cartridge fitted), because the program is laid out for the stock memory map with the screen at $1E00 and the custom character set at $1400.
Run the .d64 in xvic (the VIC-20 emulator in the VICE suite). From a terminal in the directory holding the disk image:
Windows (Command Prompt or PowerShell; use the full path to xvic.exe if VICE's bin folder is not on PATH):
xvic.exe -memory none -autostart tank-vs-uap.d64
Linux / macOS:
xvic -memory none -autostart tank-vs-uap.d64
The
-memory noneflag is required. By default VICE enables a 3K RAM expansion, which relocates the BASIC start address and prevents the disk-loaded program from landing at$1001. Tank vs UAP targets the stock unexpanded machine, so the expansion must be switched off.
The bare tank-vs-uap.prg can be started directly, but the disk image must still be attached as drive 8. The game loads its code overlays and title banners from disk at boot. -autostartprgmode 1 injects the .prg straight into RAM and types RUN, leaving the drive free for those loads.
Windows:
xvic.exe -memory none -autostartprgmode 1 -8 dist\tank-vs-uap.d64 -autostart build\tank-vs-uap.prg
Linux / macOS:
xvic -memory none -autostartprgmode 1 -8 dist/tank-vs-uap.d64 -autostart build/tank-vs-uap.prg
src/ 6502 assembly source (Kick Assembler).
build/ Build output (tank-vs-uap.prg + code overlays) and the pre-generated
banner data (banner-*.prg, banner-layout.asm, banner-resident.asm)
needed to assemble.
dist/ Disk image (tank-vs-uap.d64). Disk only for now, no tape image 'yet'.
images/ Screenshots.
The project builds with two tools, on Windows, Linux, or macOS:
| Tool | Needs | Role |
|---|---|---|
| Kick Assembler v5.x | A Java runtime (Java 8+) | Assembles src/ into the .prg binaries. |
| VICE 3.x | - | c1541 packs the .d64 disk image; xvic runs it. |
On Windows, Kick Assembler is a plain KickAss.jar download and VICE is a zip whose bin folder holds c1541.exe and xvic.exe. On Linux, install VICE from your package manager. On macOS, brew install vice provides both binaries. The commands below assume KickAss.jar at an example location and c1541 / xvic reachable on PATH. Note: substitute your own paths as needed.
Run from the project root. One invocation assembles the whole game: the main program plus all four disk-loaded code overlays. The -libdir build is required. build/ holds the pre-generated banner data files (banner-layout.asm, banner-resident.asm, and the three banner-*.prg bitmaps) that are committed to the repository and imported by the source; the -odir path must be absolute.
Windows (Command Prompt; in PowerShell replace %CD% with $PWD):
java -jar C:\Programs\KickAssembler\KickAss.jar src\tank-vs-uap.asm -libdir src -libdir build -odir "%CD%\build" -o "%CD%\build\tank-vs-uap.prg"
Linux / macOS:
java -jar ~/kickassembler/KickAss.jar src/tank-vs-uap.asm -libdir src -libdir build -odir "$PWD/build" -o "$PWD/build/tank-vs-uap.prg"
This writes tank-vs-uap.prg, overlay.prg, overlay2.prg, screens-overlay.prg, and resident.prg into build/.
c1541 formats a fresh disk and writes the program, the code overlays (single-letter disk names o / p / s / r), and the three title-screen banner bitmaps (t / a / c). Create dist/ first if it does not exist (mkdir dist).
Windows:
c1541 -format "tank vs uap,tu" d64 dist\tank-vs-uap.d64 -write build\tank-vs-uap.prg "tank-vs-uap" -write build\overlay.prg "o" -write build\overlay2.prg "p" -write build\screens-overlay.prg "s" -write build\resident.prg "r" -write build\banner-title.prg "t" -write build\banner-author.prg "a" -write build\banner-controls.prg "c"
Linux / macOS:
c1541 -format "tank vs uap,tu" d64 dist/tank-vs-uap.d64 \
-write build/tank-vs-uap.prg "tank-vs-uap" \
-write build/overlay.prg "o" \
-write build/overlay2.prg "p" \
-write build/screens-overlay.prg "s" \
-write build/resident.prg "r" \
-write build/banner-title.prg "t" \
-write build/banner-author.prg "a" \
-write build/banner-controls.prg "c"
xvic -memory none -autostart dist/tank-vs-uap.d64
| Author | Tool / Source |
|---|---|
| Duane Later | Original type-in BASIC version of Tank vs UFO. The inspiration for this game. |
| Mads Nielsen | Kick Assembler |
| The VICE Team | VICE |
Released under the MIT License — Copyright © 2021 Rohin Gosling.