After beating LittleGiant Cup, I was challenged by that trainer, like the champion challenges you after beating him. When I accepted, it brought me into what looked like a normal monster battle, with the practice and fight options. I couldn't select either so I had to refresh. In case it has any bearing on the potential glitch, I have 500 of all stats, level 30, phoenix feather, fangs of werewolf, and wings of atlantic equipped.
I think this game's pretty fun. The only real thing that I thought might help would be the ability to mute sounds separately from the music. I really like the music in this game, but the sound effects can be pretty grating, especially when you're getting a lot of money drops or you're using the minigun. But as it is, if you mute you mute sound and music.
This is a pretty good game. There are a few bugs, like if you have enough souls to put a level in a weapon and then die the souls will reset to what they were at the start of the level while your skill won't. I have max in the ankh but the achievement is locked for that very reason. Also, occasionally a completely impervious zombie will appear and you will have no hope of clearing the level. My high score run got screwed because of one. Finally, it might be on my side of things, but it seemed like the longer I played the game the more horrendous the lag was. Don't get me wrong, I really enjoyed playing through this game, but there are a few things that should probably be looked into.
 "Monster Arena"){kind=icon}
 "Notebook Wars 2"){kind=icon}
 "Soul Redeemer"){kind=icon}