I knew that sky background in WarioWare Mega Microgames looked familiar...

[CM30]

Look at it a minute:

Now look at the sky background from Wildflower Fields in Wario Land 4:

Yep, same sun and glare effect in both games.

Got to love the recycled scenery, haven't you?

 

[607]

Hm, they do look the same... Maybe they were done by the same artist?
I don't think they would look at older games for inspiration for something like lens glare.

 

[CM30]

Given how many Wario Land 4 resources were reused in Mega Microgames... I think they probably would. And there's nothing wrong with that. WarioWare was a risky endeavour back in the GBA era, so any effort/cost saving is for the best.