The assets that you re-created can be protected under multiple different intellectual property protections. Copyright protection is just one of them, but the assets can also be part of a registered trademark, industrial design right or "trade dress".
If you accidentally re-created the assets from hill climb, as in you can prove that you didn't know about their similarity until after you created the assets, then you are not infringing on the copyright of the original assets.
If, on the other hand, you knew about hill climb before creating your assets, it is likely that your assets will be seen as derivative works of the original assets and infringing on their copyright (unless you have a license to create derivative works).
In any case, if any of the other intellectual property rights are in force (they usually require an explicit registration), then your assets are definitely infringing on them. For those rights, the creation process does not matter.