Are downscaled images supposed to flicker so bad? (Linear s)

Greetings!

I have a game in which a zoomin option is an essencial feature. Naturally, to ensure zoom in linear sampling, you'd have to make all sprite texture size in game x3-x4 times the actual sprite size. The only problem here is the resulting flickering :

https://www.youtube.com/watch?v=FeHs1od7e8g

Previewed on NWjs preview.

Thanks for any help in advance.