Enter will skip any cutscene you're currently in. For that, there's a prompt halfway through for you to mash buttons in order to escape. If you do so, you move to the boss fight. If you don't, the scene continues towards a game over.
I also found something for the author, at least.
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Site seems like an alternative to Pixiv. He has three sets of images up, one from Magical Girl Ai and two from Luminous Heart. One is an extended version of the boxer enemy game over and the other is a tentacle scene not in the game yet. My Japanese is terrible sadly so I can only make out what Google Translate tells me for it.