Unfinished R-Type (U) PCE/Turbo to SuperGrafx hack by Chris Covell
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This hack converts the US TG-16 ROM (unscrambled) of R-Type into
a bi-compatible PCE/SGX ROM.  On a real SuperGrafx, flicker will
be greatly reduced, as the new limit to maximum sprites on-screen
will now be 128, as opposed to the TG/PCE's 64.

I've also expanded the screen size to full vertical height on both PCE
and SG, so the game no longer needs to scroll vertically.  To adjust the
vertical screen positioning, pause the game and hold I then press Up or Down.

This was a hacking project that I started in 2011, but abandoned
the following year, mostly because I became a father, and thus life
got too busy to work on a sustained project like this one.

(Each level has to have its scrolling, raster interrupt, priority logic,
etc. etc. hacked individually, you see.)

This hack is unfinished, and "works" to about level 4.  It still has a
debug invincibility mode that can be activated by pressing Select during
gameplay.

This is distributed in the form of an .IPS patch.  Apply the patch using
IPS patching software to an R-Type(U)ROM, (and rename it from .PCE to .SGX
if necessary for emulators/FPGA systems to activate their SGX emulation.)

I assume no responsibility for explosions caused to your hardware etc. etc.

Chris Covell, June 2019
chris _ covell -at- yahoo.ca