I'm outing myself as a shoot 'em up fan here, but why Gradius Gaiden of all games? My personal pick on the PS1 would be Thunder Force V. Since Technosoft is now defunct, the rights to that franchise belong to Sega, but I don't think Sega and Sony have any bad blood in 2018 so acquiring the rights to that series wouldn't be that difficult, would it?
(Also I think Gradius is generally a poor franchise in general)
https://www.youtube.com/watch?v=RtLowss-_5EI mean listen to this and tell me it doesn't make you want to play it, even if you hate the genre!
G-Darius is also in "it's okay but not especially amazing" range as far as proper shooters go. The PS1 isn't the most renowned shooter platform in the world, but it has a few really good ones that were unfortunately missed out on. These two picks strike me as legacy choices more than being the best the genre has to offer on the platform.
Super Puzzle Fighter instead of Puyo Puyo confuses me - Puyo was a mainstream franchise in Japan at one point, even if it isn't anymore and I don't think SPF was ever really notable in that country.
Rest of the list looks fine though. Europe
still doesn't get their hands on Parasite Eve, however.