it's really weird and nothing feels right but it probably just takes practice.
instead of true random placement for the portals, you could try making levels where you start at different points and the portals are in different spots so you can actually get a feel for how movement works. like, the first few levels you start in the middle and the portal goes to different spots, then the next few levels you start on one side or the top and you have to figure out how to move differently etc. after you get through the stages you can select a time attack mode to test your skills.
then the mode you have now could be a survival mode that has a newgrounds linked leaderboard so we can compete. and then maybe fix the true random and put an area the portal can't appear around so it doesn't just jump to the next level.