Pew... seriously, what a mess. I spent the previous few days working on the collision system. As you might have noticed, the player sometimes died when jumping on triangular tiles (and apart from that the bug BMacZero encountered seemed to be related to the collision system as well). Furthermore walking on them was somewhat "laggy". Thus I decided to rewrite the complete collision system, because it was rather badly written, and with "rather badly" I mean horrible.
Anyway, after rewriting everything two times without success I wanted to use the old, buggy but technically working system again, but for some reason it didn't work anymore, even though I hadn't changed anything related to it (well, obviously I did
change something, I just have no idea what). As consequence I had no choice but to figure out how to solve the problem, using the newest collision code I'd written.
Now, like 15 hours later, I managed to fix the major bugs and everything works indeed a bit better than before. Some new bugs appeared, but I'll eliminate them later. Anyway, ramps are not a problem anymore, hence I can concentrate on things that are actually interesting. Like sound. Finally.
@BMacZero: Thanks for the demo.