If you're referring to the post #686 pixeldrain files, you should download and combine the three parts if doing a clean install, as opposed to updating the player downloaded from post #1. The newer DMM player linked in post #766 is separated into 3 volumes and won't extract unless all 3 are downloaded, placed in the same folder, and the extraction is started from the first volume, 'DMM Kamihime_Player-1.0-pc.zip.001'.
It takes about 1 minute for my DMM player to launch. I don't have a solution for this if it persists after following the other instructions I've posted, such as updating scripts, placing files downloaded with DLpy in the correct folder path, or manually updating config.ini after 3_write_config. The '4GB Patch' mentioned in post #710 might help. I've attached a screenshot of my computer's specs according to CPU-Z so you can see if the problem is the computer's hardware, although I lack the tech savvy to understand this info.
4_download_full_art and 5_download_portrait don't work for the DMM player currently, either wait for someone to update them or download the images directly from the game as described in posts #731 and #759.
I don't think I've had this issue with the DMM player but you could try the solution used for the Nutaku player mentioned in post #773. Posting screenshots of error messages and/or LOG files can help find the source of the problem.
The newest DLpy scripts are attached to post #775 in a JPG archive. Download the Hatsune Miku image and follow the instructions in post #674. Post #762 addresses the DLpy script concerns. Basically, the Nutaku DLpy is the DMM DLpy with the URLs modified and DMM content is about 1 year ahead of Nutaku. Few of the skins (Mordred [Flower Garment] is the newest currently), none of the Divine Enlightenments, and none of the memorials are currently available on Nutaku. The screenshots in post #762 show what 000_Zest_TryDL.cmd should look like. Remove the # symbols in front of the code of the characters' JSONs you want to download and place the # symbols in front the unavailable characters and the characters you already have. Compare the contents of the downloaded JSONs to the post #762 screenshots since 'InsecureRequestWarning' messages aren't errors in the sense that it indicates a problem with the files.