I would suggest GameStart Pixel Battle: https://play.google.com/store/apps/details?id=com.eliphant.Gamestart&hl=en_US No IAP. No Ads.
GameStart Pixel Battle is a free game with no iap or ads and it still gets regular updates four years after it was released. https://play.google.com/store/apps/details?id=com.eliphant.Gamestart
Break the Targets is a good free platformer. Cally's Caves 4 is another good free game.
besides the ones mentioned by other users I found. "GameStart 2015". The camera is really close but otherwise seems decent. It even has Ryu and Chun-Li and if the description is right it's a contribution with the creator of "Street Fighter X Mega Man".
Also "Jump 'n' Shoot Attack!" is similar but not quite... I kinda like it.