Puzzle Invisible rev.II

I respectfully say a new years greeting to all MSXers at the beginning of 2017.
Anyway, let me show you my latest work.

* System requirement
This game is for MSX1 with 64KB RAM.
However, MSX2 or later is recommended for mouse support.
Play with keyboard (using cursor, space and shift key), or mouse on port 1.

* How to start
Get a zip file including a dsk image. Write the image down to 2DD and load it by real MSX. Or execute the image with an MSX emulator as you like. For your quick launch click here, and the game will start on WebMSX.

* Story
You are an administrator of cosmic route. Use phototube and searching-laser to find unknown blackholes for keeping the course safe.

* How to play
(1) Start a game
Play with mouse or keyboard. Push space key(left-click) to start a new game. At first choose game difficulty. Novice for starting stage 1; tutorial, Amateur for stage 4, or expert for stage 8.

(2) Normal stage
Push space key or left-click on any point in the matrix, and you will try something is here. If you choose a right point, the hidden object will be visible. Besides you get Laser bonus score, and playable time is extended. After you discover all of blackholes, the next stage is coming up.
A bad choice gives you a fault mark(X). Only four faults are allowed in each of stages. If you have five faults in a stage or lose all of playable time, the game is over.
You wonder how to find invisible object. Mouse over a phototube; a gray circle around the game field, and searching-laser will be launched. When the laser comes closer to a blackhole, its course will be changed as follows.
a) Absorb
The laser which bumps into a blackhole is absorbed. The phototube launching it will be blackout.

b) Refract
The laser which skims a blackholes is refracted 90 degrees to outward. Both phototubes launching and receiving it will be red-lighted.

c) Reflect
This is a special case of the refraction. The laser reaching a space between two blackholes is reflected. The phototube is white-lighted.

Refer also the tutorial; the laser is visible only in the stage 1. After stage 2, you can only see the reaction of phototubes.
(3) Bonus stage
Stage 3, 7, 11...(once per 4 stages) you can play bonus stage. Laser is automatically launched and specially visible. You just have to easily discover blackholes before all of phototubes become blue-out. Even only one fault also breaks the bonus stage, so be careful.
(4) Other objects
a) Wormhole
From stage 4, a few pairs of wormhole may exist in the field. They connect two different points. Anything flying into one of them, will come out from the other side beyond the galaxy space. Refer also a demonstration after stage 3.
b) Starship
From stage 8 except bonus stages, you will see starships fly across the game field. It avoids discovered blackholes with dexterity. However, unknown one catches and destroy it. You will lose 3,000 pts. and 5 sec. playable time as penalty.
c) Question mark
You can place a question mark at any point in the game field as pushing SHIFT key or right-clicking. It has no influence upon the game but serve as a landmark for helping with your thought. A question mark also prevent your mis-clicking a point under consideration. That means you must erase it before you try there. You just have to right-click again to take it away.
5) Hint
- Blackholes nor wormholes never exists on the outer rim of the field.
- Any blackhole never lays side-by-side on the left, right, top nor bottom of the other one.
- Any wormhole never exists on 8 points around a blackhole.
- Wormholes bring not only laser but starships even if it already discovered or not yet.

* Notes
This game is based on a board-game I played in my childhood. I can't remember the exactly name of it. Please tell to me if you know about it.
I must say special thanks to Paulo Peccin, the author of WebMSX. His great work brought a pleasure of programming on MSX back to me. This game development was fully done on his WebMSX.