On GBA, it is different to find the W3D Level because one has been spliced into two (Industrial Zone I think).
Always, by the time I get through these two, I forget to look for that bonus Level ;)
There is also one more, Level 31, which has escaped me so far
Just finished DOOM 2 again, on GBA SP 101, third time in a row, in God mode. DOOM 2 came out on PC in 1994... I am so old. And it's as much fun as ever :D
It seems so to me too. I see the overview oage only, but when e.g. clicking the Wiz section, a long black technical database message appears. Hope all is right:)
https://pyra-handheld.com/boards/threads/gp2x-bricked.99843/#post-1714086
Last year there was a discussion about "voltage regulator broken".
Maybe trying it out with non rechargeable 1.5 V batteries?
(I hope it is that easy...)