I have whole list of stuff that I have to do xD Answer to yours:
Floor is lava thats for sure going in
Speed boosts - sure, there will be slides and perfect timed rolls after landing will keep your momentum
About the rest - the multiplayer will be in trackmania style so no collisions, static map etc. because that's all I can afford XD and I don't want to over complicate things as I'm doing everything alone
Also there will be map builder so given big enough player base I'm sure people will come up with something crazy
Any feedback is great and well appreciated