The Hello Mario Engine was designed to be easy to modify in order to encourage you to try adding in new things yourself. Try it! It's not as hard as you think.
This is a myth. While many of the games share the same art style and graphics, all the games include unique levels, and most include unique gimmicks that set them apart from the rest.
This is also a myth. While old versions of the engine may have been messy, this does not apply to the latest version, which is clean, organised, and easy to modify.
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