it does those even in windows mugen.
Laggy
the engine lags like mad once you use more than few helpers.
limited
you can barely change the title screen, stages are completely non-interactive, the music can't be changed without shoddy workarounds. you can't affect the continue screen looks at all. it's impossible to disable the character select after you continue from losing. you can't define your own portraits on select screen, so you're forced to use the fixed values. so, it's impossible to do animated select screen without some serious hack jobs involving positioning of the cursor which is actually the animation and such.
glitchy
explods tend to appear incorrectly if spawned by a helper when there's a lot of them. they'll be taking another helper's point of orgin as their own.
crashy
just press q on title screen.
or, have mp3/ogg music on title screen or select screen, or anywhere else. crash guaranteed if you leave it on for a while. or hell, sometimes the crash will happen on loading, and in rare cases it can even freeze your entire pc.