It's now been confirmed, and even admitted by the OP, that the game in question won't work on NTSC consoles. The reason it works on a Retron 5 is because the console is not a "NES clone", it is little more than an emulator, which means through software (think: the firmware on the Retron 5) the system is able to deal with PAL/NTSC timing differences -- actual NES consoles (the real hardware) cannot. Nestopia is also an emulator, thus is able to accomplish the same thing the Retron 5 can.
So what exactly are you trying to do now? Testing a PAL repro cart you made for a region that you can't test on?
Are you aware that you aren't going to be able to use a PAL NES on 1) US television sets (at least most/many won't work with it) (voltage/freq issue described in #3 applies), 2) US electrical (you'll need an actual step-up or step-down transformer, not just a "wall outlet adapter", because the voltage between EU and US usually differs (often 220V vs. 120V, as well as the wavelength being 50Hz instead of 60Hz), and 3) needing PAL NES controllers (you cannot use NTSC controllers on a PAL NES, while you can use PAL controllers on an NTSC NES --
explanation here is legitimate, it's caused by a pull-up resistor)? You're up against several complications.
A more economical and reasonable approach, I would think, would be to send the cartridge you've wired to someone who does have a PAL NES and see if it works for them. There are probably people here in the US who have PAL NESes for testing (they'd need all 3 of the above things), but sending it to someone overseas would work as well.