Well Alien Breed 2 AGA and OCS are extremely similar and it's just a little bit prettier that's all.
The same goes for Tower Assault which contains both AGA and OCS on the same disks. Very little cosmetic upgrade at all.
I don't know if you can include Stardust and Super Stardust because they are different games but they are essentially very similar. Super Stardust does however look a lot nicer, much shinier and crispy. And those tunnel sections.... oooohhh