Looking for R-Type experts who can answer a few questions for the "in progress" Mega Drive version

[TheRoboZ]

Hello, I am TheRoboZ and I am currently working on MEGA R-Type, a port of R-Type for the Sega Mega Drive / Genesis.

You can find info and a Demo here: https://theroboz.itch.io/mega-r-type
No need to leave any donation.

The game progressed a lot since the demo, there are only 2 stages left to be done. I am currently working on stage 4 and am stumbled by the boss "Compiler". In most videos I have used as reference and on my own playthrough, it behaves as in the following video

https://www.youtube.com/watch?v=2xAX6XTzpg0&t=489s

but, I have seen some different behavior near the end of its sequence depending on how many parts were left before timeout. While inquiring about this on twitter, I received this video which shows a different behavior:

https://www.youtube.com/watch?v=pVWtI0426mU&t=527s

So I wonder if anyone here know exactly how the boss movement is determined. Is the difference due to being on the second, hardest, loop? Is there a different behavior depending on dip switch difficulty setting? Or is it determined by how many parts are in play and player position?

Thanks in advance.

Any help will be greatly appreciated.

[Kino]

You're in luck, the dev team touched on R-Type's programming intricacies in the Dec. '87 issue of Gamest. Although whoever answered this particular question (Sumita himself?) was a bit vague:

–What is the pattern for the movement of the st4 boss?

There are 3 patterns, and they’re chosen randomly. Actually, it isn’t completely random… maybe if you investigate a bit, you’ll discover it?

[MJR]

I've had the bootleg PCB for 24 years, and been playing it "a bit".

I never really investigated it, but that boss seems to sometimes break and change it's movement pattern when you move from one end of the screen to the other. I have never observed any other curiosities. I believe you could easily investigate this out by playing a save state in Mame.

[TheRoboZ]

–What is the pattern for the movement of the st4 boss?

There are 3 patterns, and they’re chosen randomly. Actually, it isn’t completely random… maybe if you investigate a bit, you’ll discover it?

Thanks! Now I remember reading this interview maybe 4 years ago and completely forgot about this. I'll investigate in Mame.

[Steven]

I have absolutely nothing to add, mostly because I kill the stage 4 boss as fast as I can so I don't have to put up with its semi-randomness, so I don't know that much about its behaviour.

I do want to say that I am really looking forward to this, so please make it excellent. From what I have seen so far, I am not concerned at all, although I would like the ability to freely map the buttons, as I didn't find a button layout configuration in the demo that I was 100% satisfied with. I'd prefer [SHOT] [FORCE] [AUTOFIRE] on ABC in that order, as is the standard on R-Type (and other) arcade cabinets here in Japan, so if you could add that (or maybe already did in a newer build), that would be glorious and highly appreciated.

[TheRoboZ]

I have absolutely nothing to add, mostly because I kill the stage 4 boss as fast as I can so I don't have to put up with its semi-randomness, so I don't know that much about its behaviour.

I do want to say that I am really looking forward to this, so please make it excellent. From what I have seen so far, I am not concerned at all, although I would like the ability to freely map the buttons, as I didn't find a button layout configuration in the demo that I was 100% satisfied with. I'd prefer [SHOT] [FORCE] [AUTOFIRE] on ABC in that order, as is the standard on R-Type (and other) arcade cabinets here in Japan, so if you could add that (or maybe already did in a newer build), that would be glorious and highly appreciated.

I'll add this, no problem

[Steven]

I have absolutely nothing to add, mostly because I kill the stage 4 boss as fast as I can so I don't have to put up with its semi-randomness, so I don't know that much about its behaviour.

I do want to say that I am really looking forward to this, so please make it excellent. From what I have seen so far, I am not concerned at all, although I would like the ability to freely map the buttons, as I didn't find a button layout configuration in the demo that I was 100% satisfied with. I'd prefer [SHOT] [FORCE] [AUTOFIRE] on ABC in that order, as is the standard on R-Type (and other) arcade cabinets here in Japan, so if you could add that (or maybe already did in a newer build), that would be glorious and highly appreciated.

I'll add this, no problem

Excellent, thanks!

[ben.shinobi]

The boss's movements are determined by the duality between the position of the R-9 and the timing of the frame (key frame).
In my video, I can destroy it in the same way every time using precise positioning :
https://youtu.be/Ofev-qUcXjY?si=KKj8RwqAg4WD8Kxv&t=655
How to destroy this boss is essential for the second object in stage 5 (speepdup or blue laser).
I'm currently sharing with Katsun (the best Japanese player) about random items and POW ARMOR (stage 5 & 7), which aren't actually random.
Don't hesitate to contact me on twitter or by email if you want more infos.