Panzer Paladin / vestigial Gamedesign
Don't have a lives+continue system that erases progress, players are already getting punished by being stuck !
Don't have long levels just for the sake of it, make memorable encounters !
Don't have instant death *and* sparse checkpoints that force you to repeat huge sections !
Don't have offscreen enemies you can't react to !
Please, if you make a game in a "traditional" style, think about what you put in and how you treat players, we can do better
2/2
Panzer Paladin / vestigial Gamedesign
Addendum:
I wrote "vestigial Gamedesign" because that's what this is
Most of these things are just non-functional leftovers from eras with different goals
e g. Continues -> there to make you put in more quarters
Long levels + insta death + sparse checkpoints -> more quarters
None of these lead to a more interesting or rewarding play experience
You can challenge players without disrespecting them and wasting their time