Sonic the Hedgehog 2
Level Select:
Hold A + B + C on title screen, then press Start.
It is needed for quick access to levels and testing.
Streets of Rage 2
Training / Practice:
Use the options menu to adjust lives, difficulty and sound test.
It's convenient for quick starts and balance checks.
Contra: Hard Corps
Stage practice:
Use the password / options section when available in your version.
The codes may differ for different regional versions.
Mortal Kombat
Hidden options:
Enter the options menu and explore the code / test settings.
Useful for demonstrating hidden features and settings.
Sonic 3 & Knuckles
Debug / Secrets:
Use the built-in level select and debug combinations for experimentation.
Suitable for a page with secrets and speedrunning notes.
Castlevania: Bloodlines
Password section:
Add a table of passwords for checkpoints, extra lives and stages.