The only really weird bit is the ring of lakes and rivers around the red area - I imagine something magical is happening there?
However, there is some really "challenging" geography going on here, occasionally.
The extremely long river across the continent that, I think, Coyotemax mentions. The necessity here is that the source of that river has to be sufficiently high so that all the river SW is downhill from there on, and yet, a short distance away is the coast to the NW, past that other smaller lake. This area would be extremely steep to accomodate the same drop to sea level as taken by the long river (which also passes a couple of decent mountain ranges to get there).
A similar situation occurs on the Western continent around the large lake - the inflow river on the lake's NE side comes from very close to the coast - which would imply extremely high cliffs there or something.
In general, personally, I would tend to view "with suspicion" any river that appears to flow "inland". It's certainly not impossible, but you have to ask yourself why it is happening when there are mountains about. In plains areas it's not such a bother.
It's a lovely map, albeit I'm no expert on mapping. It's possible that this scale may warrant "filering" out some of the rivers if you have difficulties with space to represent other stuff.
Good luck!