When I beat a level, the game stays on the score screen for minutes. It tells me to press spacebar to start next level but it doesn't work. However, pressing spacebar seems to make the character jump since I hear the jumping sound, though the screen still shows the inter-level screen.
On the console, I can see lot of lines like this: "[0474.78] ScriptLog: TPC: In IgnoreInput State"

In case someone stumbles upon the same problem, I've found a workaround which solves the problem in www.forum.towerofguns.com/viewtopic.php?f=2&t=3268&start=10 .
Instead of running the game with ./start.sh, the workaround is to run it with LANG=C ./start.sh