I don't have the brain energy to do a full list of pivotal youth games but here's a deep cut pick

「rRootage」 NORMAL 0A～0R プレイ動画

Oh shit I remember this

I was fond of many of the works of ABA Games

some other big ones

Tumiki Fighters - 5,500,000 points

a horizonal shmup where when you destroy enemies/pieces of enemies you can catch them and add them to your sihp

Torus Trooper Extreme Difficulty 6,256,549 Points

Gunroar Highscore - 110 Million

ABA Games

whole collection is here