1. Contra 4 is worst the Contra ever; not because it sucks, but because it does absolutely nothing that every other Contra before it didnt already do making it a very been there done that experience. A numbered entry should always mean an official advancement and Contra 4 was a retread.
2. You are essentially asking why cant Contra in 2019 be like Contra from the 80's. Gamers have to stop acting like that every game IP has to be in a box contrained by whatever era it was created in.Think about all your favorite long running franchises; It they were contrained to whatever they were created in what would you not have right?.
I think everybody is being overly harsh based on presentation. It doesn't look spectacular, but it doesn't say anything about its potential of at it least being a good game, not phenomenonal, just good.
There is nothing wrong in following a formula, at least to a certain extent. After years of absence, if the new game is radically different than the ones that came before, people are going to be wary, especially coming from "I charge for saveslots" Konami. Considering how many 2D sidescrollers are around, and how well they usually sell (for indie standards), a game with pedigree should do fine if it continues its formula. Instead, it looks like Konami took an entirely different game and put the Contra logo on it.
You know it deserves the GOTY.