VirtualMIDISynth is a software MIDI synthesizer based on the Microsoft Windows MIDI Mapper. It is a free and open source software that allows users to play MIDI files using their sound card's built-in synthesizer. It is designed to replace the old Windows MIDI Mapper and provide users with more features, such as virtual instruments, more control over sound parameters, and the ability to use their own sound banks. VirtualMIDISynth also supports multi-timbral playback, which allows users to play multiple tracks in one MIDI file. Additionally, the app is compatible with various popular MIDI sequencers and DAWs, such as Cubase, Reason, and Ableton Live.
You can use this to make the midi output sound good, with the right sound source (I recommend "FluidR3 GM.SF2").