I don't outright hate Sonic 4, but in a lineup of Sonic 1, 2, CD, 3&K, Chaotix, and Mania, Sonic 4 is easily the worst.
Episode I: The physics are, in fact, genuinely awful. Sonic doesn't carry any momentum at all, you have to hold a direction to keep moving in it. Let go, and Sonic falls straight down in midair and grinds to a halt while grounded. Addtionally, in certain situations Sonic can actually stand on walls or walk slowly up them, something that should never be able to happen. You cannot gain speed by rolling down hills, and in fact lose speed trying. All this combined makes him very unsatisfying to control.
The level design is pretty terrible too. It's usually pretty simplistic, with most acts focusing on a single gimmick. On top of that, while I do actually like the music, it's generally pretty generic compared to other OST's in the franchise.
The game was originally actually meant to be a mobile exclusive game titled "Sonic the Portable", which honestly if it kept that title it likely would have been cut some slack.
Episode II: A solid improvement, but still not enough to stand alongside the other classic series games. The physics aren't as terrible, the music is much better, the levels are a bit more original, and the tag team actions are a breath of fresh air on the formula. The game is quite fun to play with friends, and still has my favorite special stages.
Episode Metal: A crime for just existing. It's everything wrong with Episode I on steroids, with really dickish level design and enemy placement. It feels like SEGA hired some kid to make a "lol hard" romhack style level pack for Episode I with a Metal Sonic skin over Sonic and no real understanding on how to do difficulty properly in a Sonic game. How could they do my bouncy blue metal boy dirty like that?
Overall, aside from Episode Metal, Sonic 4 is generally pretty inoffensive, but it's not really anything great either. Episode II has the most merit to play due to having more of it's own identity, otherwise you'd be genuinely better off just playing Sonic 1. That's my opinion in a nutshell, anyway.
Yea, I don't
outright hate Sonic 4 like I do some other titles. But if we compare it to the game that "came before it", it's far worse, hell, I'd argue it's worse than CD.
I'll tackle my thoughts now.
First of all, one of the original points was saying that the level design was similar to Sonic 2, which is the peak of Classic Sonic level design to the OP (I don't agree with that, but each to their own. I personally think Sonic 3 was best. Remember, Classic Sonic wasn't about speed. It was about flow.)
Looking at maps, at first glance I'd agree, BUT then we get to the gimmicks point.
Most of S4 Ep. 1's levels involve a singular gimmick or none at all. S4 Ep. 2 is a bit better in this regard, as I can remember multiple gimmicks from Sylvania Castle.
Secondly... physics.
If this game wants to state itself to be "Sonic 4", then it should live up to what made the Classic games so great. This was primarly the physics. S4 Ep. 1? It's physics pale in comparison to the original triology. S4 Ep. 2 still is worse off, but they DID make efforts to fix it.
The differences include:
- Momentum? What's that.
- Jump gets cut straight down if you let go of jump.
- Etc.
The music could probably be way better
if it wasn't using fake Genesis synth. Both full-on rearrangements AND true Genesis rearrangements sound far better. It's the same thing holding back the Classic Sonic OST in Forces!
However, the main issue causing much of the criticism
is that it's meant as a mobile game. SEGA, in it's infinite wisdom, decided "Hey, let's push the simple mobile game as a big console game meant to be the legitimate successor to Sonic 3, the Classic Sonic game people praise as being great!" Cue what happens most times you port a mobile game to console: it's seen as mediocre and nothing to care about. Had SEGA not done what they did, Sonic 4 would be Sonic the Portable and would be in a similar spot to Sonic Dash and Sonic Forces Speed Battle nowadays: neat, but nothing of note.
TL;DR: Treat Sonic 4 as a mobile game and then you get what it was developed to be. Treat it as SEGA wants you to and you have all rights to be pissed, as it's trying to say that it lives up to be a successor to a game a lot of the community praises immensely. However, if you like it, that's fine. It'd have been a decent mobile game.