Sonic CD honestly is a lot more like Sonic 1 than Sonic 2, it does take a few steps back from Sonic 2, but I find it to better than Sonic 2 even though it doesn't take as many risks. Sonic 2 was made by an American team, while Sonic CD was made by a Japanese team and so there's a bit of a difference in philosophy of how the games were designed. Sonic 2 is a lot more about being cool and stylish, but I found Sonic CD is a super atmospheric game and the soundtracks (both American and Japanese) really help sell that. I found there to be a lot more quieter moments in Sonic CD and I found that really helps make the game feel more special and unique compared to RUN EVERYWHERE AND KILL EVERYTHING, I wouldn't however want this in every game but sometimes the quieter moments are quite lovely. Sonic CD as a consequence of being on the Sega CD originally looks amazing and is nice to look at and on the eyes even for a colourblind person like me.

Sonic CD like Sonic 1 has 3 acts per zone with the final one being a shorter boss level which works in terms of this being a mobile port where it saves at the start of every act, less so in the original release where there wasn't saving- especially at the start of the each act. The stages are pretty short as well with more a focus on exploration, but I found the game to be fun to go however I wanted to go. I discovered some secrets like using the main gimmick of this game- Time Traveling. With time traveling you can go to the past or to the future, which completely changes the graphics of the stage and if you want the true ending bonus content.

As much as I love this game, I do have to acknowledge the faults and have to be realistic even if I do love this game. The level design despite the quieter moments does fall a bit flat and are boring even with exploration, the themes aren't really unique either and just feel like rehashes of sonic 1's or something sonic 2 did better. The level names themselves are really nice alteration though, but that doesn't change how I feel about the levels themselves. The worst the game got was Wacky Workbench 1 which was a confusing maze, but it wasn't insufferable, just waited like 8 minutes of my time.

​The bosses are very easy, with most not even requiring to hit them, which is unique but it's like that until the final boss and it gets kinda stale by the end. It makes sense from a story point of view, I suppose even at the cost of difficulty. Most bosses took less than a minute to beat. This game does get some bonus points for having a boss which isn't eggman being Metal Sonic, but Metal Sonic isn't used much and has 1 boss fight which is a race, but doesn't make sense.

Overall, I love this game but it does fall flat with some level design and boss designs even if I did have fun. Definitely my favourite between sonic 1, sonic, 2, and sonic CD.

Sonic 2 is one of those games where I really really hate it at points, but at other times it is amazing, honestly this game leaves me with a lot of mixed emotions.

This game or well the original version of it, introduces Spin dashing (which was possible in the sonic 1 port for mobile devices as well), Super Sonic, Tails, and two acts per zone instead of three (meaning more unique zones in total). These are all pretty good features and have become a staple in the series since and why I like the franchise.

Sonic 2 honestly has pretty good level design, half of the time, and well the other half of the time it falls flat right on it's face. I am glad the level design for the most part has improved since Sonic 1 because I don't think I could handle more of that. Unfortunately 2 of the worst zones Chemical Plant starting with ACT 2 and both Aquatic Ruins acts are as bad as the worst levels from sonic 1 for me and it especially sucks they're the 2nd and 3rd zone respectively. Chemical Plant Act 2 just has downright unfair level design that punishes you for making a simple mistake and it's especially true for Aquatic Ruins (the worst of the two for me) where sometimes you get hit by random dropping pillars or an arrow that shoots from the left of the screen at random and is hard to see which is a problem the stage has in general because it's colours are wayyyyy too bright. Luckily unlike sonic 1, there are zones I enjoy more than just the first one (in this case Emerald Hill Zone) with Casino, Hill Top, Mystic Cave, and Oil Ocean) all being highlights for me as well as the first stage.

However, the rest of the stages are pretty mediocre and feature not great level design like what was seen in the first game. Metropolis zone ACT 1 and ACT 2 are mediocre with some minor unfair level designs that could kill you randomly, but for some reason this stage has 3 ACTs and the third one is EXTREMELY hard and unfair and I'm not really sure how I got past it. Lots of cheap deaths in this level in particular. Sky Chase zone is unique and that you're on a plane flying throughout the whole level, but there's no ground and Tails will go under you when you fly and it just doesn't feel quite right and like I'm about to fall at any moment along with some minor enemy spam. Wing Fortress is solid, but there's one part where you can't see very well to the right of you and you're expected to make basically blind jumps and hope you get to the other side which basically ended most of my runs on this level and was frustrating.

Then there's Death Egg zone which is the stage I'm the most mixed on, this game is downright unfair on the original version of this game and I would have rated this game like 2 stars otherwise, but it gets an extra half star due to saving. Without saving you're expected to fight 2 boss fights in a row (20 hits total) with zero rings and the bosses have a set pattern as well that you're expected to memorise. I HATE these bosses, but I found myself having more and more fun trying to speedrun this stage the more I tried it and I ended up loving it. However what isn't fun is the hitbox on Eggman, the game doesn't properly display how to beat this boss and it is frustrating as hell without looking it up and even with looking up how to beat the boss it took me 2 hours, and I... kind of liked it? It felt fun towards the end and felt extremely satisfying to defeat the bosses and see the credits roll. Honestly, if I didn't have fun on this stage by the end, I would have rated this game 2 stars even with the saving feature.

Besides the levels, the rest of the bosses are pretty okay to fun. There is one weird oddity with the mobile version in particular, which is the fact there's a Hidden Palace Zone (which was scrapped from the original release of Sonic 2), it's an okay stage (not anything too special), however if you die on the stage it sends you back to Mystic Cave (which is how you enter it) which is annoying for trying to find the level again. I ended up not defeating the boss due to this.

Overall, I love and hate this game and it's left me feeling very mixed about it. The level design is all over the place from very high highs to very low lows without too much in-between.

I love this game, all of the way until Marble zone then the game becomes terrible. The problem with this game is, the first stage and it's 3 acts (meaning you have to playthrough 2 variations on top of the original stage itself, later games use 2 acts for the most part) are amazing and make you feel fast and cool (which is how the game was marketed). Then it all comes tumbling down with Marble Zone. Marble Zone is super slow, more about pushing, and punishing you for going too fast. IT SUCKS. It goes against everything the game has taught you to that point and it gets worse from there with some glimpse of hope.

After that there is Spring Yard zone, which is not bad, but not good either and then the infamous Labyrinth zone (which takes place underwater for the most part), which is just as bad as people say it is. Labyrinth zone is full of level design you can't really see in front of you a lot of the times and this part is almost as slow (but, ever-so slightly faster) than marble zone. You have to get air bubbles a lot just so you can breathe underwater for a while, IT SUCKS. This is an absolute game-killer on top of awful Marble zone and I was almost ready to quit here.

Then, there is Star Light zone which is about on part with Spring Yard, gets a bit hahaha death in the third act, but nothing too too bad. After that there is Scrap Brain zone which is about on par with Star Light zone act 3 for acts 1 & 2, and then there is Scrap Brain zone act 3. Scrap Brain zone act 3 made me consider just giving up on the game entirely. IT IS slow paced, filled with water like in Labyrinth zone, and uses air bubbles which are different than the ones in Labyrinth zone (even though they use the same graphic) and they're much MUCH slower too. I was struggling so much with the fact that the air bubbles weren't spawning, because there's a lot in-between each air bubble spawn location. I was only able to beat this level because of the fact I had 2 air bubbles randomly spawn SOMEHOW at the very end which were the first time I saw any in the stage. The stage itself is also filled with obstacles you can't see very well either sometimes.

Finally, there is the final boss. If this wasn't the final boss I would have quit. You get NO rings before you enter and it is slow and repetitive and complete bullshit. You basically have to stand on one corner and hope you get the boss to spawn near you so you can hit it 8 times. I'm so glad I was playing the mobile version where you save at the start of each level, because I wouldn't have made it here otherwise.

Other things of note, the bosses are mediocre and not really memorable. The music is excellent, which is what makes this game not too dreadful. The mobile controls for the mobile port are not too terrible, but they can hinder sometimes and not get the input you want. This game in it's original state doesn't have the iconic spin dash introduced in Sonic 2, but it is added to a lot of modern ports.

Overall, this game sucks and I recommend playing it just for the first level and the 3 acts it has to offer otherwise avoid this game.