ZX Spectrum game · play free
Gemquake
Mine 25 crystal caverns with a pod and a ball. Catch falling capsules for multiball, lasers, fireballs and a wider pod, and set off chains of TNT.
In short
- Gemquake is an original bat-and-ball game for the ZX Spectrum 48K and 128K, in the Breakout tradition.
- There are 25 named caverns, from First Dig to The Motherlode, and then a faster second loop.
- About one broken brick in eight drops a capsule: multiball, lasers, fireball, bomb ball, wide pod and more.
- Every pickup is announced on screen, so you always know what you've caught.
- The title screen keeps a top-five table with initials, score and level reached.
How to play Gemquake
You steer a mining pod along the bottom of the screen and keep a ball in play, breaking the crystal walls above. Where the ball hits the pod decides its angle: near the middle sends it up steeply, near the ends sends it out wide. The ball speeds up as the rally goes on, up to a limit set by each cavern.
You start with three pods and earn another every 40,000 points, up to nine. Clear a cavern for a time bonus, plus 5,000 points if you didn't lose a pod.
The bricks
| Brick | What it does |
|---|---|
| Coloured bricks | 10 points (blue) up to 70 points (white) |
| Armoured bricks | Take two or three hits, and look cracked on the last one |
| Gold bricks | Unbreakable: aim around them |
| TNT (flashing) | Blows up its eight neighbours, and can set off other TNT in a chain |
Break four bricks in a row without the ball touching your pod and the combo multiplier climbs, all the way to five times the points. It resets the moment the ball comes back to you.
Capsules and power-ups
- M Multiball: three to ten balls at once.
- F Fireball: smashes straight through bricks for 10 seconds.
- B Bomb ball: blows up bricks around it for 15 seconds.
- L Lasers: hold fire to shoot for 15 seconds.
- W Wide pod, C Catch, S Slow, and + an extra pod.
- N Narrow and Q Quick make life harder but are worth 400 points each.
- ? Mystery: could be any of them, and the game tells you which.
Active power-ups show as badges on the bottom row and blink in their last three seconds. If no brick breaks for 20 seconds, a helpful capsule drops from the top to break the stalemate.
Tips
- Use the edges of the pod to send the ball into gaps between gold bricks.
- Save TNT for last in TNT Alley and Chain Reaction: one hit can clear half the screen.
- Catch the ball before lasers, so you can line up your shots before launching.
- Warp ahead: once you've reached levels 6, 11, 16 or 21 in a session, you can start there from the title.
How Gemquake was made
Gemquake is written in Z80 assembly and runs entirely without the Sinclair ROM, with its own interrupt routine and 8.8 fixed-point ball physics. The cavern designs are generated by a script that checks every breakable brick can actually be reached past the gold ones. An autopilot cleared all 25 caverns on both the 48K and the 128K, and every one of the eleven power-ups was measured to check it really works.
On a 128K you'll hear "Crystal Fever" on the title screen and "Pickaxe Boogie" in the caverns, with five variations as you go deeper. On a 48K the game plays its original beeper tunes.
Bat-and-ball games were everywhere on the 8-bit computers. Our ZX Spectrum history covers the arcade conversions of the 1980s, and our guide to writing a Spectrum game today shows how games like this are made now.
