Very cool first game jam entry!! Simple and fun, I like it. I like the mix of 2D and 3D art, and I quite like the way you showed the player's direction with the arrow. I suppose it's not really necessary in this game context, but I think it looks cool :). My main critique is that the movement gets a jittery after you've touched any of the radiation. It's not deal-breaking, but it definitely gets a little annoying and would be a tiny fix that might make things feel a little smoother.
Nice work and (what I'd call) a very successful first game jam! :)