Recently, Muv-Luv photonmelodies♮ got released on Steam. The game is a visual novel that has three adventure stories and one of them is a sequel to Muv-Luv Alternative. Current special 10% off release price is $26.99 or ¥2821.85 until August 5. For more details, check out the store page. Here's the opening trailer.
Official Website: https://muvluv.com/