Super Mario: Blue Twilight DX is described as 'non-profit unofficial fangame based on the Mario universe. It combines elements from 3D Mario titles with classic, 2D gameplay, set in Halloween-themed levels'. There are more than 25 games similar to Super Mario: Blue Twilight DX for a variety of platforms, including Windows, Mac, Linux, Android and iPhone. The best alternative is SuperTux, which is both free and Open Source. Other Super Mario: Blue Twilight DX like games are Cave Story (Dokutsu Monogatari) (Free), Braid (Paid), Hollow Knight (Paid) and Mari0 (Free, Open Source).
Cave Story, or Dokutsu Monogatari, is a Japanese freeware Metroidvania side-scrolling Metroidvania platform-adventure game developed by Studio Pixel . It has been translated into English by Aeon Genesis Translations.
Alex the Allegator is a series of games that I, Johan Peitz, usually use for game coding challenges like Speedhack and Ludumdare. Whilst most of my games reside on Free Lunch Design, this is the place for the Alex' series and the even the source for these games. Let's go! Represent entire series of Alex the Allegator games including Alex the Allegator 1, 2, 3, and 4.
Super Meat Boy is a platform game developed by Team Meat and is the successor to Edmund McMillen's and Jonathan McEntee's flash game, Meat Boy, originally released on the Newgrounds website in October 2008.