Sonic x Shadow Generations is basically a bundle of 2 good games in one batch. But they both have their own pros and cons.

+ Good remaster of Sonic Generations.
+ Shadow Generations is the way I wanted to see that solo Shadow game from PS2. It was also great to see Metal Overlord and Mephiles! It's fantastic game, but quite short for me. The last two levels were quite fun and challenging, still!
+ Fun to complete and gather all collectibles (except for last bit in Shadow Generations).
+ For achievements you only need to complete main stages for rank S, which is quite easy, actually.
+ Chao are cute and I still want a new version of Chao Garden in next games
+ Remastered songs are great!

- Removal of life systems, but you can still buy lives in the Skill shop. (You can still turn them on in settings, but why not make lives active by default?)
- Removal of restarting from checkpoints. It is very annoying. When you are gathering red rings or collection boxes and missed a part where both characters are running non-stop from one checkpoint to other is infuriating.
- Very stupid map system in Shadow Generations. Map is completely useless - you can not set pins, collectible boxes are just marked if you see them or when they are opened. And the worse part is those robots part. You WILL waste your time on the last part, so I would suggest you to use guide.
- Red ring 2 in City Escape Act 2.

Overall, this bundle is fantastic! I really enjoyed it and got all achievements with relative ease.

8 CHAOS CONTROL out of 10

I've Completed this game 3 times now and about to Complete it a 4th :3

great game from sega you all should try this