Nice update! Here's something funky: press and hold select to enable hard mode (nice flame effect btw), then press start to go into sound test, you'll see a "05" under the "sounds" number. This doesn't happen if you enter sound test with the titlescreen in normal mode.
The game normally does this. What you're seeing is the level display for the level select code: Level 5 is the first level of Hard Mode. When the game is set to Normal, the level ID on this is blank (The sound test won't display level 1's ID), so you don't see it.
To initiate the level select code, press and KEEP HELD the Start button to choose Normal Game, and hold Select+A+B. While still holding Start, hit Select+A+B to increment the level counter once in the sound test. Exit the sound test, and you'll begin on that stage.
(FYI, 1-4 are the Normal Mode stages, 5-11 are Hard Mode and 12 is the Time/Score Attack stage)
Also, some people have complained about the new title screen, so I've added an alternate patch in the archive above with a title truer to the original:
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Use either on a clean Recca ROM; I'm not sure what will happen if you patch one over the other, so play it safe.