1a) You must submit an IPS file, NOT a ROM of any kind!
Use this tool to create your IPS file, and put the patch in a ZIP. Commercial ROMs are illegal, and we will not host any on this site. Uploading a ROM will result in a 72-hour ban for the first offense, and if you do so again, you will be permanently banned from SMW Central.
4) Your hack should be of a reasonable length!
Unless you intend to make your hack contain very long and very high quality levels, demos which are too short to provide any feedback on or be enjoyable will be subject to removal. A general rule of thumb is that the hack should feature at least one complete world with about five levels, or should feature around at least 15 minutes of game time.